Del Air Rockhounds Club, Inc

The Del Air Rockhounds Club Welcomes You!!

2012-12-31T11:11:00.000-08:00

The Del Air Rockhounds Club was founded in 1952 with members mostly residing in the San Fernando Valley area of California. Our club is a non-profit organization dedicated to sharing knowledge of the lapidary arts and techniques, geology, mineralogy and related fields. We own our own lapidary equipment with members available to teach and demonstrate lapidary techniques to other members. Our members enjoy lapidary related programs, demonstrations, exhibitions, displays and lectures. We also take monthly field trips to our local deserts & mountains for exploration and the study and collection of lapidary and mineral specimens.

BIG NEWS!!!! BIG NEWS!!!! BIG NEWS!!!! BIG NEWS!!!!

THE DEL AIR ROCKHOUNDS

GEMBOREE SHOW IS COMING!!

Del Air Gemboree Show February 24th and 25th 2012

2012-03-04T21:38:00.000-08:00

The Del-Air Rockhounds invite you to join us for our annual GEMboree Show on Friday February 24th 2012 from 3-9 pm
and Saturday February 25th 2012 from 10 am-5 pm.

Admission and parking is free!

Please right click on the flyer to the left to open it in a new window. From this new window you will be able to print the flyer.

Write your name, address and phone # on the back and bring it with you to the show to be entered into a special web-only drawing for a spectacular door prize. Winners need not be present to win.

FIND UNIQUE GIFTS - CRYSTALS – FOSSILS – GEMS – BEADS

YOUTH GAMES – PRECIOUS STONES – DISPLAYS

SPHERES – MINERAL SPECIMENS – HANDMADE JEWELRY

See you all at the show!!

January 2012 Rock of the Month

2012-01-04T20:13:00.001-08:00

Granite

Granite is the signature rock of the continents. More than that, granite is the signature rock of the planet Earth itself. The other rocky planets—Mercury, Venus and Mars—are covered with basalt, as is the ocean floor on Earth. But only Earth has this beautiful and interesting rock type in abundance. Three things distinguish granite. First, granite is made of large mineral grains (which is where its name came from) that fit tightly together. Second, granite always consists of the minerals quartz and feldspar, with or without a wide variety of other accessory minerals. The quartz and feldspar generally give granite a light color, ranging from pinkish to white. But that light background color is punctuated by the darker accessory minerals. Thus classic granite has a "salt-and-pepper" look. The most common accessory minerals are the black mica biotite and the black amphibole hornblende. Third, almost all granite is igneous, meaning it solidified from a fluid state and almost all granite is plutonic, meaning it did so in a large, deeply buried body or pluton. The random arrangement of grains in granite is evidence of its plutonic origin. Granite is found in large plutons on the continents, in areas where the Earth's crust has been deeply eroded. This makes sense, because granite must solidify very slowly at deeply buried locations to make such large mineral grains. Plutons smaller than 100 square kilometers are called stocks, and larger ones are called batholiths. On the grandest scale, granite represents the way the continents maintain themselves. The minerals in granitic rocks break down into clay and sand and are carried to the sea. Plate tectonics returns these materials through seafloor spreading and subduction, sweeping them beneath the edges of the continents. There they are rendered back into feldspar and quartz, ready to rise again when and where the conditions are right.

October 2011 Fossil of the Month

2011-10-05T19:41:00.000-07:00

Amber

Amber is fossilized tree resin (not sap), which has been appreciated for its color and natural beauty since Neolithic times. Amber is used as an ingredient in perfumes, as a healing agent in folk medicine, and as jewelry. Because it originates as a soft, sticky tree resin, amber sometimes contains animal and plant material as inclusions. Amber occurring in coal seams is also called resinite, and the term ambrite is applied to that found specifically within New Zealand coal seams. Amber is globally distributed, mainly in rocks of Cretaceous age or younger. Historically, the coast around Konigsberg in Prussia was the world's leading source of amber. About 90% of the world's extractable amber is still located in the Kaliningrad Oblast of Russia on the Baltic Sea. Pieces of amber torn from the seafloor are cast up by the waves, and collected by hand, dredging, or diving. Elsewhere, amber is mined, both in open works and underground galleries. Amber occurs in a range of different colors. As well as the usual yellow-orange-brown, amber itself can range from a whitish color through a pale lemon yellow, to brown and almost black. Other more uncommon colors include red amber, sometimes known as "cherry amber", green amber, and even blue amber, which is rare and highly sought after. Much of the most highly-prized amber is transparent, in contrast to the very common cloudy amber and opaque amber. Opaque amber contains numerous minute bubbles. This kind of amber is known as "bony amber". Although all Dominican amber is fluorescent, the rarest Dominican amber is blue amber. It turns blue in natural sunlight and any other partially or wholly ultraviolet light source. In long-wave UV light it has a very strong reflection, almost white. Only about 100 kg is found per year, which makes it valuable and expensive. Sometimes amber retains the form of drops and stalactites. It is thought that, in addition to exuding onto the surface of the tree, amber resin also originally flowed into hollow cavities or cracks within trees, thereby leading to the development of large lumps of amber of irregular form.

September 2011 Mineral of the Month

2011-08-31T20:33:00.000-07:00

Petrified Wood

Petrified wood comes from the Greek root petro meaning "rock" or "stone"; literally translating to "wood turned into stone". It is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into stone by the process of permineralization. All the organic materials have been replaced with minerals, mostly silica such as quartz while retaining the original structure of the wood. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen. This inhibits aerobic decomposition. Mineral-laden water flowing through the sediment deposits minerals in the plant's cells and as the plant's lignin and cellulose decay, a stone mold forms in its place. In general, wood takes less than 100 years to petrify. The organic matter needs to become petrified before it decomposes completely. A forest where the wood has petrified becomes known as a Petrified Forest. Elements such as manganese, iron and copper that are present in the water or mud during the petrification process give petrified wood a variety of color ranges. Pure quartz crystals are colorless, but when contaminants are added to the process the crystals can take on a yellow, red, or other tint. Petrified wood can preserve the original structure of the wood in all its detail, down to the microscopic level. Structures such as tree rings and the various tissues are often observed features. Petrified wood has a Mohs hardness of 7, the same as quartz. Petrified wood is the provincial stone of Alberta, Canada and also the state gem of Washington.

July 2011 Fossil of the Month

2011-07-06T19:04:00.000-07:00

Ammonites

Ammonites or ammonoids (both terms are used interchangeably) are an extinct group of marine invertebrate animals in the subclass Ammonoidea of the class Cephalopoda. These mollusks are more closely related to living coleoids (i.e. octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species. Ammonites are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods. Their fossil shells usually take the form of planispirals, although there were some helically-spiraled and non-spiraled forms as well. The name ammonite, from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams' horns. Pliny the Elder (circa. 79 AD. near Pompeii) called fossils of these animals’ ammonis cornua ("horns of Ammon") because the Egyptian god Ammon was typically depicted wearing ram's horns. Ammonites first appeared in the Devonian Era (circa 400 MYA) and became extinct at the close of the Cretaceous around 65 MYA along with the dinosaurs. Few of the ammonites occurring in the lower and middle part of the Jurassic period reach a size exceeding 9 inches in diameter. Much larger forms are found in the later rocks of the upper part of the Jurassic and the lower part of the Cretaceous, such as Titanites from Jurassic of southern England, which are often 2 feet in diameter and another species of the Cretaceous period of Germany, which is one of the largest known ammonites, have been known to reach 6.5 feet in diameter. The largest documented North American ammonite is Parapuzosia bradyi from the Cretaceous with specimens measuring 4.5 feet in diameter, although a newly discovered 7.5-foot British Columbian specimen, if authentic, would appear to trump even the European champion

June 2011 Fossil of the Month

2011-06-01T20:17:00.000-07:00

Trilobites

Trilobites, meaning "three lobes”, are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record dates back to the early Cambrian period approximately 526 million years ago. They flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Devonian, all trilobite orders with the sole exception of Proetida, died out. Trilobites finally disappeared in the mass extinction at the end of the Permian about 250 million years ago. The trilobites were among the most successful of all early animals, roaming the oceans for over 270 million years.

When trilobites first appeared in the fossil record they were already highly diverse and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton an extensive fossil record was left, with some 17,000 known species spanning the Paleozoic era. The study of these fossils has facilitated important contributions to biostratigraphy, paleontology, evolutionary biology and plate tectonics.

Trilobites had many life styles; some moved over the sea-bed as predators, scavengers or filter feeders and some swam, feeding on plankton. Most life styles expected of modern marine arthropods are seen in trilobites, with the possible exception of parasitism where there is still some scientific debate. Some trilobites are even thought to have evolved a symbiotic relationship with sulfur-eating bacteria from which they derived food. Trilobites range in length from .04 inch to 28 inches, with a typical size range of 1-4 inches. The world's largest trilobite, Isotelus rex, was found in 1998 by Canadian scientists in Ordovician rocks on the shores of Hudson Bay. It measured 28 inches long by 16 inches wide by 3 inches high.

May 2011 Fossil of the Month

2011-05-04T20:24:00.000-07:00

Corals, Crinoids & The Like

Crinoid Coral Head
Sand Dollar

Crinoids are unusually beautiful and graceful members of the phylum Echinodermata. This is the phylum that brings you starfish, sea urchins, and sand dollars. The crinoids are a breed apart however, they resemble an underwater flower. Some even have parts that look and act like roots anchoring them to the ocean floor. They are commonly called sea lilies. Their graceful stalks can be meters long. Other varieties have no stalks or root like parts. They are commonly known as feather stars. Unlike the sea lilies the feather stars can move about on tiny hook like structures called cirri. Crinoids are alive and well and living in an ocean near you! They are also some of the oldest fossils on the planet. The earliest come from the Ordovician Period. Most of the Paleozoic forms died out in the great Permian extinctions. The few species surviving into the Mesozoic Era thrived. Many new species evolved during this time including the ancestors of the present day class Articulata. Corals are among the most colorful animals in the sea. Most corals live in warm, shallow, tropical seas and feed on plankton. The oldest fossil corals are from the Ordovican period, over 450 million years ago. Corals are marine animals with a sac-like body, mouth, tentacles and skeleton. It is the skeleton that survives in the fossil record. Of the varieties of fossilized corals found throughout the world exquisitely detailed specimens from the mountains of Indonesia are among the most unique. In Indonesia, entire coral heads are often completely preserved and appear just as they did 20 million years ago, although their density is much changed by replacement with silica, iron, manganese and other minerals. There are fern corals, brain corals, hex corals, honeycomb corals and many more. Florida and Georgia in the USA are also import sources of fossil coral. In fact Florida has declared fossil coral to be the Florida State Rock. Fossil coral pieces are sought after by gemstone and fossil collectors around the world as well as being used in beads and other jewelry.

Crinoid Coral Stem

Crinoid

March 2011 Fossil of the Month

2011-03-02T19:04:00.000-08:00

Fossil Plants

Paleobotany, from the Greek words “paleon”, meaning old and "botany", meaning the study of plants), is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts.

A plant fossil is any preserved part of a plant that has long since died. Such fossils may be prehistoric impressions that are many millions of years old, or bits of charcoal that are only a few hundred years old. Prehistoric plants are various groups of plants that lived before recorded history (before about 3500 BC). Plant fossils can be preserved in a variety of ways, each of which can give different types of information about the original parent plant.

1. Adpressions (compressions-impressions). These are the most commonly found type of plant fossil. They provide good morphological detail, especially of dorsiventral (flattened) plant parts such as leaves. If the cuticle is preserved, they can also yield fine anatomical detail of the epidermis. Little other detail of cellular anatomy is normally preserved.

2. Petrifactions (anatomically preserved fossils). These provide fine detail of the cell anatomy of the plant tissue. Morphological detail can also be determined by serial sectioning, but this is both time consuming and difficult.

3. Molds and casts. These only tend to preserve the more robust plant parts such as seeds or woody stems. They can provide information about the three-dimensional form of the plant, and in the case of casts of tree stumps can provide evidence of the density of the original vegetation. However, they rarely preserve any fine morphological detail or cell anatomy. Subsets of such fossils are pith casts, where the center of a stem is either hollow or has delicate pith. After death, sediment enters and forms a cast of the central cavity of the stem.

4. Authigenic mineralization. These can provide very fine, three-dimensional morphological detail, and have proved especially important in the study of reproductive structures that can be severely distorted in adpressions. However, as they are formed in mineral nodules, such fossils can rarely be of large size.

5. Fusains. Fire normally destroys plant tissue but sometimes charcoalified remains can preserve fine morphological detail that is lost in other modes of preservation; some of the best evidence of early flowers has been preserved in fusains. Fusains fossils are delicate and often small, but because of their buoyancy can often drift for long distances and can thus provide evidence of vegetation away from areas of sedimentation.

February 2011 Fossil of the Month

2011-02-02T19:59:00.000-08:00

Fossil Sea Shells

Imagine that you are hiking in California’s blazing desert, 100 miles from the Pacific coastline. Imagine the huge mountains and the winding canyons that would surround you. Cacti dot the sandy landscape. What is the last thing you would expect to find? Seashells! Yet find them you will: in dried out washes, on an ancient shell reef, in canyon walls. Located 20 to 25 miles west of today’s El Centro, California, the basin offers a vast shell bed of 6-million-year-old oyster fossils. Erosion has left the dry wash streambeds littered with the shells. Strata in the streambed walls clearly show where oysters once covered the basin floor. California’s Shell Reef, located in the middle of an active off-road vehicle area in Anza Borrego State Park, is another treasure trove of fossils. Although a small fence protects the reef, you can still enter the area and examine the fossilized oyster shells. Shell Reef formed about four million years ago. We could also search America’s Great Plains, more than 1000 miles east of the California Desert. Any chance we might find seashells there, in the middle of the continent? You bet. The shells provide evidence of an ancient sea – the Western Interior Seaway – that existed in what is now America’s Heartland. Over time, the Western Interior Seaway receded, leaving the floor exposed. Vast rock and sediment layers remain along with fossils from creatures that once lived in the sea. The Pierre Shale is a formation deposited by the Western Interior Seaway. Exposures occur in Canada and in many U.S. states, including South Dakota, Colorado, Nebraska, Minnesota, New Mexico and Wyoming. The shale contains many species of fossilized shells, including ammonites, which we will be covering in depth as they are scheduled to be a future fossil of the month.

January 2011 Fossil of the Month

2011-01-05T19:21:00.000-08:00

Fossil Teeth

Shark------------------ Megalodon----------

Alligator----------- Orca Killer Whale

The most commonly found fossil teeth are shark teeth although mammoth, mastodon, horse, bison, primate, and the teeth of skates, rays, whales and dolphins are also highly sought after. In general, the larger the tooth the more valuable although value is also based on whether the fossil teeth are rare. For example, mastodon teeth are smaller than mammoth teeth but are more valuable due to the rarity of the mastodon teeth. Fossil teeth found take many different forms. Many animals, including mammoths, sharks and reptiles go through quite a few sets of teeth during their lifetime, making it easier to find them.

Mammoth teeth are often found after being tossed around by the ocean for many years, so their appearance may be rounded. Mammoth teeth from the Pleistocene can be found in the North Sea, Alaska and Russia among other places.

Mastodon teeth are most commonly found from the Shovel-Tusker Mastodon, since the teeth from the American Mastodon are much harder to find. Both the Shovel-Tusker Mastodon and the American Mastodon are a part of an extinct group of proboscidians with cusped molar teeth.

The teeth of a shark are the only part of its body that is easy to fossilize because they are made up of bone while the rest of the shark is made up of cartilage. Small shark teeth are extremely common on some East Coast beaches but larger fossilized shark teeth are harder to find. The Megalodon shark was over 40 feet long and is now extinct. Fossil teeth from this shark are extremely valuable and are about 3 times as big as the teeth from a great white shark. Alligator teeth are commonly found in Florida. These fossil teeth are very important to the study of terrestrial vertebrates in North America. Many species of fossil whale teeth can be found in both North & South Carolina as well as several other locations around the world.

Mosasaur----------Mammoth-------Shark

October 2010 MIneral of the Month

2010-10-06T20:05:00.000-07:00

Brazilian Agate

Brazilian agate is a variety of chalcedony and comprised of cryptocrystalline quartz. It has a hardness of 6.5 to 7.5 on the Mohs scale. It occurs in bands of varying color and transparency. The Brazilian varieties are characterized by peculiarities in the shape and color of the bands, which can be seen in sections when cut at right angles to the layers. The banding in Brazilian agates forms as silica from ground water is slowly deposited into cavities and veins in the older rock. Agate is found throughout the world as nodules in volcanic or other eruptive rock and also in hollow geode form. Brazil is a major producer of agates. Agates are identical in chemical structure to jasper, flint, chert, petrified wood, and tiger's-eye, and are often found in association with opal. The colorful, banded rocks are used as a semiprecious gemstone. Brazilian agates can be artificially stained to produce a combination of colors more vivid than those found in the natural state. The agates from Brazil are mostly mined from decomposed volcanic ash and basalt from the late Permian age (248-275 million years ago) In Rio Grande do Sul the "agate mines" are normally just plowed fields in which loose agates are found and collected. Brazilian agates are very colorful stones with some of the most beautiful inclusion and structures imaginable. Agate is very hard and takes an excellent polish. Sadly, most of the market for Brazilian agates is for the dyed versions of these stones. When you see a pink,teal, purple or green agate it is dyed and not natural.

Support the Rock Chippers and attend their show this Month!

2010-10-06T19:39:00.000-07:00

Please support the Rock Chippers and attend their show.

!! FREE ADMISSION!! !! FREE ADMISSION!! !! FREE ADMISSION!!

An educational non-profit community organization

WOODLAND HILLS ROCK CHIPPERS, INC.

TWELFTH ANNUAL

GEM SHOW

Saturday, 10:00 am – 5:00 pm FIRST UNITED METHODIST CHURCH

OCTOBER 16, 2010 22700 Sherman Way, West Hills, CA 91303

CRAFTS - FOOD - JEWELRY – DEALERS

GEMS ٠ MINERALS - ROCKS ٠ FOSSILS

DISPLAYS ٠ DEMOS - SILENT AUCTIONS

HANDS-ON ACTIVITIES THROUGHOUT THE DAY

FOR INFORMATION E-MAIL

info@rockchippers.org

!! FREE ADMISSION!!

September 2010 Mineral of the Month

2010-09-01T19:15:00.003-07:00

Ocean Jasper

Ocean Jasper is a silicon dioxide mineral that occurs in highly silicified rhyolite. This means that it is in the Quartz family and just like all other Jaspers it has a hardness of 6.5 to 7. Ocean Jasper is sometimes called Orbicular Jasper, a broad term given to several Jaspers displaying perfect circles throughout the piece. The peculiar orbs or "bull's eye" patterns are caused when Quartz and feldspar crystallize in radial aggregates of needle shaped crystals. A few of these other Orbicular Jaspers are Poppy Jasper and Leopard Skin Jasper. Many of these other orbicular jaspers are found in various locations throughout the world; however none are as rare as Ocean Jasper! The vibrant colors visible in Ocean Jasper are caused by many different minerals. Red is caused by iron or hematite, light yellow or gray is caused by clay and brown or deep yellow is from goethite. Sometimes a dazzling display of sparkling tiny crystals occurs upon the surface. These little gems, known as druze, are the result of clear or white quartz formations. Many collectors seek specimens of Ocean Jasper with these unique crystals upon them. Another exceptional quality of Ocean Jasper is translucency. Many specimens are opaque and still very beautiful while others, when held in front of a strong light source, display what can only be described as another world! When viewed in front of a bright light the translucent or clear background illuminates and displays the contrasting solid orbs, which then reveal exactly why Ocean Jasper is sometimes called "Fish Eye Jasper". These solid spheres appear suspended in the illuminated quartz. Each piece of Ocean Jasper seems to have a mind of its own! For example, in some specimens a solid opaque background of mustard yellow contrasts with hundreds of tiny green circles. In others, a sparkling white surface displays diagonal lines of pink and red running in every direction. Almost every piece of Ocean Jasper displays at least one of the orbs, striking colors, crystal displays or translucency. The story of Ocean Jasper began many years ago. It was the early 1950's in Madagascar when a prospector brought Paul Obeniche of Madagascar Minerals Co. a sample of the curious new orbicular jasper. The prospector could not recall the source of the sample, however Paul estimated it may have been from the northwest coast of Madagascar. Reaching this particular location was extremely dangerous due to treacherous reefs, sheer rugged cliffs and no roads. The effort to find it was fruitless and this new Orbicular Jasper was soon forgotten. About 45 years later, photos of this unnamed Jasper reappeared in the Mineralogical Encyclopedia. This sparked everyone's curiosity and the Madagascar Mineral Company sent out several expeditions again. In 1999, after 45 days of visiting fishing villages along Madagascar's NW coast, the Orbicular Jasper was once again discovered! Luckily the expedition was sailing near Moravato, along the NW coast during low tide. As the strong ocean currents pushed back from the cliffs, the beautiful Orbicular Jasper was seen once again!

September 2010 Mineral of the MOnth

2010-09-01T19:15:00.001-07:00

July 2010 Mineral of the Month

2010-06-30T20:05:00.001-07:00

HOWLITE

Howlite, a calcium borosilicate hydroxide (Ca2B5SiO9(OH)5), is a silicate mineral found in evaporate deposits. Howlite was discovered at Tick Canyon, California in 1868 by Henry How (1828-1879) He was a Canadian chemist, geologist, and mineralogist. In appearance, it is white with fine gray or black veins in an erratic, often web-like pattern, and is opaque with a sub-vitreous luster. Slabs of Howlite are often painted with scenes and designs that make artistic use of these veins. Its structure is monoclinic with a Mohs hardness of 3.5 and lacks regular cleavage. It is most often found in massive nodules that resemble a head of cauliflower and rarely in crystal form as tabular prisms.

Howlite is commonly used to make decorative objects such as small carvings or jewelry components. Because of its porous texture, Howlite can be easily dyed to imitate other minerals, especially turquoise because of the superficial similarity of the veining patterns. Howlite is also sold in its natural state, sometimes under the misleading trade names of "white turquoise" or "white buffalo turquoise", or the derived name "white buffalo stone". Sometimes Howlite fluoresces a blue, yellowish white or off white color under shortwave UV light and dissolves in hydrochloric acid solution without bubbling.

June 2010 Mineral of the Month

2010-06-02T19:22:00.001-07:00

Prehnite

Prehnite is the first mineral ever to be named after a person, and was first described in 1789 for an occurrence in Haslach, Harzburg and Oberstein, Germany., It is named for Colonel Hendrik Von Prehn commander of the military forces of the Dutch colony at the Cape of Good Hope from 1768 to 1780. Prehnite is a member of the silicates family of minerals. It is brittle with an uneven fracture and a vitreous to pearly luster. Its hardness is 6-6.5, its specific gravity is 2.80-2.90 and its color varies from light green to yellow, but also colorless, blue or white. It is mostly translucent, and rarely transparent. Though not itself a zeolite, it is found associated with minerals such as datolite, calcite, apophyllite, stilbite, laumontite and heulandite. It occurs in veins and cavities of basaltic rocks and sometimes in granites and gneisses. Prehnite crystallizes in the orthorhombic crystal system, and most often forms as stalactitic or botryoidal aggregates with only just the crests of small crystals showing any faces. There are no commercial uses for Prehnite other than collecting, carving and jewelry making. This, of course, makes it the perfect lapidary material for rockhounds.

May 2010 Mineral of the Month

2010-05-05T19:31:00.000-07:00

'Spinel'

The name Spinel comes from the Latin word ‘spina’ meaning ‘thorn’ in reference to its sharp sided crystals. Spinel is a member of the oxides mineral group. Spinel crystallizes in the isometric system; common crystal forms are octahedral, usually twinned. It has an imperfect octahedral cleavage and a conchoidal fracture. Its hardness is 8, its specific gravity is 3.5-4.1 and it is transparent to opaque with a vitreous to dull luster. It may be colorless, but is usually various shades of red, blue, green, yellow, brown or black. There is a unique natural white spinel, now lost, that surfaced briefly in what is now

Sri Lanka

. Some spinels are among the most famous gemstones: Among them is the Black Prince's Ruby and the 'Timur Ruby' in the British Crown Jewels, and the 'cote de Bretagne' formerly from the French Crown jewels. The Samarian Spinel is the largest known spinel in the world, weighing 500 carats. True spinel has long been found in the gemstone-bearing gravel of

Sri Lanka

and in limestones in

Afghanistan

and in Mogok,

Burma

. Recently gem quality spinels were found in the marbles of Luc Yen in

Vietnam

, the Mahenge and Matombo regions in

Tanzania

, the Tsavo region in

Kenya

and in the gravels of Tunduru in

Tanzania

and Ilakaka in

Madagascar

. Spinel is found as a metamorphic mineral, and also as a primary mineral in igneous rocks. In these igneous rocks, the magmas are relatively deficient in alkalis relative to aluminum. Aluminum oxide may form as the mineral corundum or may combine with magnesium to form spinel. This is why spinel and ruby are often found together.

April 2010 Mineral of the Month

2010-03-31T19:38:00.000-07:00

CHRYSOPRASE

Chrysoprase is a gemstone variety of chalcedony (a cryptocrystalline form of silica) that contains small quantities of nickel which provide it with its apple green to deep green color. The darker varieties of chrysoprase are also referred to as prase. The word chrysoprase comes from the Greek chrysos meaning 'gold' and prason, meaning 'leek'. As with all forms of chalcedony, chrysoprase has a hardness of 6 - 7 on the Mohs hardness scale and a conchoidal fracture like flint. The best known sources of chrysoprase are Queensland, Western Australia,

Germany

Poland

Russia

, Arizona, California, and

Brazil

. The chrysoprase and Ni silicate ore deposit in Szklary, Lower Silesia,

Poland

, was probably the biggest European chrysoprase occurrence and possibly also the biggest in the world. Chrysoprase was used by the Greeks, Romans, and the Egyptians in jewelry and other ornamental objects and because of its semi-opaque green color; it is often mistaken for Imperial jadeite. One of the most valuable chalcedony gem stones, chrysoprase is prized for its color and rarity. The stone occurs in serpentine rocks and in weathered materials of nickel ore deposits as nodules or in veins within the host rock

March 2010 Mineral of the Month

2010-03-02T19:43:00.000-08:00

Hemimorphite

Hemimorphite is a sorosilicate mineral which has been mined from days of old from the upper parts of zinc and lead ores, chiefly associated with smithsonite. It was often assumed to be the same mineral and both were classed under the same name of calamine. In the second half of the 18th century it was discovered that there were two different minerals under the heading of calamine - a zinc carbonate and a zinc silicate, which often closely resembled each other.

The silicate was the rarer of the two, and was named hemimorphite because of the hemimorph development of its crystals. This unusual form, which is typical of only a few minerals, means that the crystals are terminated by dissimilar faces. Hemimorphite most commonly forms crystalline crusts and layers, also massive, granular, rounded and reniform aggregates, concentrically striated, or finely needle-shaped, fibrous or stalactitic, and rarely fan-shaped clusters of crystals.

Some specimens show strong green fluorescence in shortwave ultraviolet light and a weak light pink fluorescence in longwave UV.

Hemimorphite most frequently occurs as the product of the oxidation of the upper parts of sphalerite bearing ore bodies, accompanied by other secondary minerals which form the so-called iron cap or gossan. Hemimorphite is an important ore of zinc and contains up to 54.2% of the metal.
Hemimorphite is a member of the silicates group. Its hardness is 4-1/5 to 5 on the Mohs scale. It has an uneven to conchoidal fracture and a perfect cleavage. It can be white, colorless, blue, greenish, gray, yellowish or brown and has a colorless streak. It is transparent to translucent with a vitreous luster. It will give off water when heated in a closed tube and is soluble in acids with gelatinization.

February 2010 Mineral of the Month

2010-02-03T19:25:00.000-08:00

Mica Group

Zinnwaldite Biotite

The word "mica" is thought to be derived from the Latin word micare, meaning "to glitter", in reference to the brilliant appearance of this mineral especially when in small scales.

The mica group of sheet silicate (phyllosilicate) minerals includes several closely related materials having highly perfect basal cleavage. The five most common Micas are: Phlogopite, Biotite, Zinnwaldite, Lepidolite and Muscovite. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition. The highly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms.

Phlogopite Lepidolite

Mica is widely distributed and occurs in igneous, metamorphic and sedimentary regimes. Large crystals of mica used for various applications are typically mined from granitic pegmatites. Until the 19th century, large crystals of mica were quite rare and expensive as a result of the limited supply in Europe. However, their price dramatically dropped when large reserves were found and mined in Africa and South America during the early 1800s. The largest sheet of mica ever mined in the world came from a mine in Denholm, Quebec, Canada. Scrap and flake mica is produced all over the world. Flake mica comes from several sources: the metamorphic rock called schist as a by-product of processing feldspar and kaolin resources, from placer deposits, and from pegmatites. Sheet mica is considerably less abundant than flake and scrap mica. Sheet mica is occasionally recovered from mining scrap and flake mica. The most important sources of sheet mica are pegmatite deposits.

Muscovite

Mica has several industrial uses including “Isinglass Mica” which are sheets of mica used as peepholes in boilers and lanterns because they are less likely to shatter compared to glass when exposed to extreme heat. Mica has a high dielectric strength and excellent chemical stability, making it a favored material for manufacturing capacitors for radio frequency applications. It is also used as an insulator in high voltage electrical equipment.

January 2010 Mineral of the Month

2010-01-06T19:33:00.000-08:00

SULFUR

Named from the Middle English word 'sulphur' meaning brimstone. Crystals are usually yellow to yellowish-brown blocky dipyramids with thick tabular and disphenodal crystals being less common. Native sulfur is usually formed from volcanic action as a sublimate from volcanic gasses associated with realgar, cinnabar, and other minerals. It is also found in some vein deposits and as an alteration product of sulfide minerals. It can also be formed biogenically, a major source being salt domes, where it has formed by the bacterial decomposition of calcium sulfate.

Sulfur is a member of the native elements group and has a hardness of 1-1/2 to 2-1/2 on the Mohs Scale. Its specific gravity is 2.0 to 2 .1. Sulfur has a resinous luster and an imperfect cleavage with an uneven to conchoidal fracture. Its chemical composition is S

Sulfur fuses at the relatively low temperature of 113 degrees and gives off choking fumes of sulfur dioxide when burned. There are many industrial uses of sulfur ranging from matches and fireworks to rubber.

November 2009 Mineral of the Month

2009-11-04T19:54:00.000-08:00

PYROMORPHITE

Named in 1813 from the Greek for "fire" and "form" because after being melted into a globule a sample will begin to take on a crystalline shape during cooling.

Pyromorphite is a secondary lead mineral found in the oxidized zones of lead deposits. Typically found as green, yellowish, brownish, greyish or white barrel-shaped hexagonal prisms, in clusters or as druses on matrix. The individual crystals are often modified or etched, giving a hopper-like appearance. This lead chloride phosphate forms a complete series with mimetite and vanadinite.

Pyromorphite is a member of the phosphates group and comes in at 3-1/2 to 4 on the Mohs Scale. It has a hexagonal crystal system with a resinous luster. It is transparent to translucent with a brittle tenacity and indistinct cleavage. Its fracture is irregular and uneven. Its chemical composition is Pb5(PO4)3CI. Its specific gravity is 6.5 to 7.1

Pyromorphite can commonly form pseudomorphs after Galena and Cerussite. There are no commercial uses for this mineral other than providing dazzling display specimens for collectors worldwide.

October 2009 Mineral of the Month

2009-09-30T20:01:00.000-07:00

BENITOITE

Benitoite was first described in 1907 by George D. Louderback, who named it benitoite. "as it occurs near the head waters of the San Benito River in San Benito County, California." It is the California State gemstone.

Benitoite is a rare blue barium titanium silicate mineral found in hydrothermally altered serpentinite and also in schists. Benitoite fluoresces under short wave ultraviolet light, appearing light blue in color.

Benitoite is a member of the silicates group. It comes in at a 6-6-1/2 on the Mohs Scale. It has a conchoidal to uneven fracture and an indistinct cleavage. It has a trigonal/hexagonal crystal system with a vitreous luster. Benitoite is typically blue, purple, pink, white, colorless and often multicolored. The stone is transparent to translucent with a colorless streak. Its chemical composition is BaT1Si3O9.

Benitoite is typically found with some combination of natrolite, joaquinite and neptunite on a greenish-gray serpentinite base.

Benitoites' main uses are as collectors' specimens, especially in specimens which show off its commonly associated minerals. Benitoites' hardness also makes it suitable for use as a gemstone, though the general lack of suitable material has limited this use.

September 2009 Mineral of the Month

2009-09-01T19:35:00.000-07:00

AZURITE

Its name comes from the Persian word 'Lazhward', meaning 'blue', in reference to its color.

There are over 45 well-known forms, and over 100 forms have been described. Azurite is often pseudomorphed to Malachite, and the two are very frequently found together.
It is a member of the carbonates group and its chemical composition is Cu3+2(CO3)2(OH)2.
It has a perfect cleavage and has a conchoidal fracture. It is a very soft stone coming in at 3-1/2 to 4 on the Mohs Scale. Its specific gravity is 3.77 to 3.78.
This mineral's typical crystal system is monoclinic. It forms as tabular and short prismatic crystals which may be twinned. It also occurs in massive, nodular, stalactitic and earthy habits.
It is usually a rich deep azure blue. The streak is a paler blue. Azurite varies from transparent to opaque and it has a vitreous or dull luster.
Azurite forms in the oxidized regions of copper deposits. It is a secondary mineral formed by the action of carbonated water acting on copper-containing minerals
Azurite is soluable in hydrochloric acid with effervescence. It fuses easily and will turn black when heated.
The intense color of Aurite makes it a popular collector's stone. However, bright light, heat, and open air all tend to reduce the intensity of its color over time. To help preserve the deep blue color of a pristine Azurite specimen, collectors should use a cool, dark, sealed storage environment similar to that of its original natural setting.
Azurite was used as a blue pigment for centuries. Depending on the degree of fineness to which it was ground, and its basic content of copper carbonate, it gave way to a wide range of blue hues.

July 2009 'Specimen' of the Month

2009-06-30T13:58:00.000-07:00

Hello All, This month, in honor of our July program, we will be changing our mineral of the month to our 'Specimen of the Month'.........................."STROMATOLITES"

'STROMATOLITES'

Stromatolites are not only Earth's oldest of fossils, but are intriguing in that they are our singular visual portal into deep time on earth, the emergence of life, and the evolving of the beautiful forms of life of modern time. A small piece of stromatolites encodes biological activity perhaps spanning thousands of years. In broad terms, stromatolites are fossil evidence of the prokaryotic life that remains today, as it has always been, the preponderance of biomass in the biosphere. For those that subscribe to the theory of the living earth, it is the prokaryotes that maintain the homeostasis of the earth, rendering the biosphere habitable for all other life. They maintain and recycle the atomic ingredients of which proteins, the essence of life, are made, including oxygen, nitrogen and carbon. We humans are, in simple terms, bags of water filled with proteins and prokaryotic bacteria (the bacteria in your body outnumber the cells in your body about 10 to 1). We humans have descended from organisms that adapted to living in a prokaryotic world, and we humans retain (conserved in evolutionary terms) in our mitochondria the cellular machinery to power our cells that we inherited from the prokaryotes of deep time on earth.

Scientists disagree on how to define stromatolites. A common definition goes something like: A lamiated rock formed by the growth of blue-green algae (i.e., cyanobacteria)". This definition is, in fact, such a gross oversimplification as be scientifically useless. It does contain a modicum of truth, however, in that the largest volume of stromatolite formations was likely formed by biogenic processes involving photosynthetic cyanobacteria. Cyanobacteria’s metabolic byproduct, oxygen, rusted the earth, pumped enormous oxygen poison to them into earth’s atmosphere, and in so doing paved the way for aerobic-based life to emerge and diversify; cyanobacteria’s contributions to life led to their own prodigious decline.

Stromatolites and their close cousins the thrombolites, are rock-like buildups of microbial mats that form in limestone- or dolostone-forming environments. Together with oncoids (formerly called "algal biscuits" or "Girvanella"), they typically form by the baffling, trapping, and precipitation of particles by communities of microorganisms such as bacteria and algae. In some cases, they can form inorganically, for example when seawaters are oversaturated with certains chemicals resulting in precipitation. Stromatolites are defined as laminated accretionary structures that have synoptic relief (i.e., they stick up above the seafloor). Stromatolite-building communities include the oldest known fossils, dating back some 3.5 billion years when the environments of Earth were too hostile to support life as we know it today. We can presume that the microbial communities consisted of complex consortia of species with diverse metabolic needs, and that competition for resources and differing motility among them created the intricate structures we observe in these ancient fossils. Microbial communities diversified through time, with eukaryotic organisms eventually joining the mix.

Excluding some exceedingly rare Precambrian fossils such as the Ediacaran fauna, stromatolites and are the only fossils encoding the first 7/8th of the history of life on earth. They encode the role that ancient microorganisms played in the evolution of life on earth and in shaping earth's environments. The fossil record of stromatolites is astonishingly extensive, spanning some four billion years of geological history with the forming organisms possibly having occupied every conceivable environment that ever existed on earth. Today, stromatolites are nearly extinct in marine environments, living a precarious existence in only a few localities worldwide. Modern stromatolites were first discovered in Shark Bay, Australia in 1956, and throughout western Australia in both marine and non-marine environments. New stromatolite localities have continued to be discovered in various places such as the Bahamas, the Indian Ocean and Yellowstone National Park, to name but a few localities.

June Mineral of the Month

2009-05-25T20:00:00.000-07:00

'Garnet Group'

Garnet is named from the word 'grantum', meaning pomegranate, for its resemblance to the fruit's seeds.

The Garnet mineral group is compromised of isomorphous minerals identical in crystal structure and in many cases difficult to determine one from another. The members of this group intermingle with one another, within limits.

The most common Garnet members are Pyrope-Mg₃Al₂Si₃O₁₂ Alamandine-Fe²⁺₃Al₂Si₃O_{12 Spessartine-}Mn₃Al₂Si₃O_{12 Andradite-}Ca₃Fe³⁺₂Si₃O_{12 Grossular-}Ca₃Al₂Si₃O_{12 and
Uvarovite-}Ca₃Cr₂Si₃O₁₂

There are seven lesser known members of the Garnet family known as Knorringite, Majorite, Calderite, Goldmanite, Schorlomite, Kimzeyite & Morimotoite. There are also two hydro garnet members know as Hibschite and Katoite. These nine members are extremely rare and very little is actually known about them.

Garnet crystals are dodecahedral or trapezohedral in form. They usually form as rounded grains and come in a variety of colors depending on the individual variety. They can also form in massive, granular or compact habits

Garnets are a member of the silicates group. They have a hardness of 6-1/2 to 7-1/2 on the Mohs scale. Garnets have no cleavage and and un-even to conchoidal fracture. It's specific gravity is 4.1 to 4.3. Garnet has a white streak and is transparent to opaque and has a vitreous luster.

Garnets form in a variety of ultrabasic igneous rocks, associated serpentines & metamorphosed rocks such as schist.

Garnet fuses fairly easily and is virtually insoluble in acids. Garnet is one of the only gemstones on the planet that is not heat treated or irradiated or undergoes any other type of man made process in order to enhance the quality of the finished gemstone.

May 2009 Mineral of the Month

2009-05-25T18:56:00.000-07:00

'TOURMALINE GROUP'

From the Cingalese word"tourmali," this was the name given to colored gem 'zircons' found on the island of Sri Lanka (Ceylon). It wasn't until the early 1800s that it was discovered that some of these "zircons" arriving in European gem centers from the far east were actually a previously un-described mineral.

The trigonal crystals formed by this group are often vertically striated. These crystals may be rounded triangular in cross-section. It also forms in massive and compact habits. Seven distinct species make up the Tourmaline group. They are Elbaite (multi hued), Schorl (black), Buergerite and Dravite (brown), Rubellite (pink), Chromedravite (green) and Uvite (black, brown, yellowy green). Crystals are often pink at one end and green at the other and may be of considerable size. Tourmalines form in granites and pegmatites as well as in some metamorphic rocks. They may be found with a wide array of minerals including beryl, zircon, quartz and feldspar.

Tourmaline is a member of the Silicates group. It has a colorless streak, is transparent to opaque and has a vitreous luster. It has a very distinct cleavage and an uneven to conchoidal fracture. Tourmaline has a hardness of 7 to 7-1/2 on theMohs scale. It's complicated chemical compsoition is as follows: Na(Mg.Fe,Li.Mn.Al)3Al6(BO3)3Si6.O18(OH.F)4

This group is insoluble in acids. The darker minerals tend to fuse with more difficulty than the red and green varieties.

April 2009 Mineral of the Month

2009-04-01T20:15:00.000-07:00

'BERYL'

The name beryl may possibly come from the greek word 'beryllos' which refers to a number of blue-green stones in antiquity. This precious gemstone mineral occurs as prismatic crystals which are sometimes terminated with small pyramids. The crystals are often striated parallel to their length and may be of massive size. Specimens up to eighteen feet long have been recorded. It also forms in massive, compact and columnar habits. The color varies greatly and gives rise to named varieties one might recognize such as Emerald, Morganite, Heliodor, Goshenite and Aquamarine. There is also a variety in red that was once referred to as Bixbite but has since been proved to be incorrect. This red variety is referred to as Red Beryl. Beryl is a member of the silicates group. Its chemical composition is Be3AI2SI6O18. It is quite durable coming in at 7-8 on the Mohs Scale. It is transparent to translucent with a vitreous luster. It has a white streak. Its specific gravity is 2.6 to 2.9. It has an indistinct cleavage with and uneven to conchoidal fracture.

Beryl of various colors is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural Mountains, and limestone in Colombia. Beryl is often associated with tin and tungsten ore bodies. Beryl is found in Europe in Norway, Austria, Germany, and Ireland, as well as Brazil, Colombia, Madagascar (especially morganite), Russia, South Africa, the United States, and Zambia. U.S. beryl locations are in California, Colorado, Idaho, New Hampshire, North Carolina, South Dakota, and Utah.

March 2009 Mineral of the Month

2009-03-04T18:52:00.000-08:00

"RHODOCHROSITE"

The name Rhodochrosite comes from the Greek, rhodom, meaning rose and chrosis meaning a coloring refering to it's color. Rhodochrosite commonly occurs as a primary gangue mineral in moderate to low temperature hydrothermal veins also in high temperature metasomatic deposits and sedimentary manganese deposits or more rarely as a late stage hydrothermal mineral in pegmatites.

This mineral sometimes forms as rhombohedral, scalenohedral, prismatic or tabular crystals. More often, rhodochrosite occurs in massive, granular, stalactitic, glogular, nodular or botryoidal habits.

Its color is typically pink to red though it may also be brown, orange or yellowish. Manganese is what gives rhodochrosite its vivid pink to red color. The streak is white. It is transparent to translucent and has a vitreous to pearly luster.

It is a member of the carbonates family and its chemical composition is MoCO3. It is very soft coming in at 3-1/2 to 4 on the Moh's Scale. Its specific gravity is 3.7 and has an uneven fracture. Its cleavage is perfect rhombohedral.

Rhodochrosite is soluble in warm hydrochloric acid with effervescence.

Del Air Gemboree this Weekend! February 27-28, 2009

2009-02-16T14:19:00.000-08:00

The Del Air Rockhounds Show is NEXT Weekend!!
See YOU There!!
CLICK HERE -To Listen to our Audio Ad!!

FREE ADMISSION AND FREE PARKING!
SHOP LATE! – FRIDAY, FEBRUARY 27^TH
WE’RE OPEN FROM 3PM TO 9:30 PM
SHOP EARLY! - SATURDAY FEBRUARY 28^TH

WE’RE OPEN FROM 10AM TO 5:00 PM

THE GEMBOREE IS AT 9650 RESEDA BLVD

AT THE CORNER OF SUPERIOR IN NORTHRIDGE

BEHIND THE UNITED METHODIST CHURCH!

We need ALL Members to help make it a successful show!!

February 2009 Mineral of the Month....'FELDSPAR'

2009-02-01T13:43:00.004-08:00

'FELDSPAR GROUP'

UPPER LEFT: FELDSPAR; UPPER RIGHT: MICROCLINE var AMAZONITE; LOWER LEFT: LABRADORITE

Feldspar is a group of silicate minerals that is comprised of Albite, Andesine, Anorthite, Anorthoclase, Banalsite, Buddingtonite, Bytownite, Celsian, Dmisteinbergite, Hyalophane, Labradorite, Microcline, Oligoclase, Orthoclase, Paracelsian, Plagioclase, Reedmergnerite, Sanidine, Slawsonite, Stionalsite, and Svyatoslavite.

Feldspar is derived from the German words Feld meaning field and Spat meaning rock that does not contain ore. Feldspathic refers to materials that contain feldspar.

Feldspar is the name of a group of rock forming minerals which make up as much as 60% of the Earth's crust.

Feldspars crystallize from magma in both intrusive and extrusive igneous rocks. They can also occur as compact minerals, as veins and are also present in many types of metamorphic rock.
Feldspars are also found in many types of sedimentary rock.

Feldspar is a common raw material used in the production of ceramic and geopolymers. Feldspars are used for thermoluminescence dating and optical dating in earth sciences and archaeolgy. Feldspar is an ingredient in Bon Ami household cleaner. Feldspar is also used as an anti-caking agent in powdered forms of non-dairy creamers.

Feldspars are relatively hard at 6 on the Moh's Scale. Feldspars are generally light-colored including white, pink, tan, green or gray. The colors will vary due to impurities within the crystal structure. Feldspar is the mineral that gives Granite its pink, green or gray color,

Feldspar is mined from large granite bodies called plutons by geologists. They are also mined from pegmatites that were formed when the last fluid stages of a crystallizing granite became concentrated in small liquid and vapor-rich pockets. This allows the growth of extremely large crystals.

UPPER LEFT: ALBITE with QUARTZ; UPPER RIGHT: FELDSPAR; LOWER LEFT: ORTHOCLASE

Del-Air Education Team To Give Talk At Local Library

2009-01-23T22:16:00.000-08:00

February 7th 2009 - 1:00 pm at the Woodland Hills Library
22200 Ventura Blvd. between Topanga Cyn Blvd. & Shoup

MAP

FREE!!!
Club members Keri Dearborn and Maxine Dearborn will be giving a talk on "Ice Age Animals". This should last for about an hour and is for adults and children. They will have a large collection of ice age bones, artifacts and pictures along with the Del-Air Education Team's specimens to enlighten, entertain and educate you on all the ice age animals. Take the time to stop by and see our exceptional education team in action.

2009 GEMboree Show

2009-01-13T20:25:00.000-08:00

Attention All Rockhounds!!

Bring the whole family to the 2009 San Fernando Valley

Gem & Mineral Show in Northridge!

For two days only, Friday Feb 27 and Saturday Feb 28 2009.

Find unique gifts, crystals, fossils, gems, beads, youth games,

precious stones, displays, demonstrations, spheres ,mineral

specimens and handmade jewelry.

Free admission and free parking!

Shop late Friday February 27. From 3:00 pm to 9:30 pm

Shop early Saturday February 28. From 10:00 am to 5:00 pm

The GEMboree is located at:

Northridge United Methodist Church

9650 Reseda Blvd., Northridge, CA

Off the parking lot on Superior Ave behind the church.

See Pictures from last year!!

Sponsored by the Del-Air Rockhounds Club Inc.

A 501 c3 registered California non profit educational corp.

2009-01-04T14:00:00.000-08:00

Happy New Year To All Del-Air Members and All Interested Guests! Please scroll below to see a calendar of events for this years happenings in Quartzite, AZ. I do not know who posted this but I send out a hearty Thank You as this is useful information for rockhounds to have.

And now.........January 2009's Mineral of the Month.........'WULFENITE'

Discovered in 1845, the mineral Wulfenite, is named after Austrian Jesuit mineralogist Franz Xavier von Wulfen, who authored a monograph on the lead ores of Bleiberg, Austria. Wulfenite forms square shaped, tabular crystals and also prismatic crystals. Other habits are massive and granular. Wulfenite is typically colored orange or yellow but may be brown, gray, or greenish brown. The colors often appear brilliant. Wulfenite forms in the parts of the ore veins that have been altered by circulating fluids, mainly water. Wulfenite can occur with a great variety of other minerals, including cerrusite, limonite, vanadinite, galena, pyromorphite, malachite, and mimetite. Wulfenite fuses easily. It is soluble in heated hydrochloric acid but will dissolve much more slowly in cold acid.

It's chemical properties are as follows:

Group: Molybdates
Crystal Structure: Tetragonal
Chemical Composition: PbMoO4
Hardness: 2-1/2 to 3 Mohs Scale
Specific Gravity: 6.5 to 7
Cleavage: Distinct Pyramidal
Fracture: Subconchoidal
Luster: Vitreous
Transparency: Translucent, Opaque
Streak: White
Tenacity: Brittle
Melting Point: 1065 o Celcius

HAPPY NEW YEAR!! - QUARTZITE 2009 IS COMING!

2009-01-02T08:18:00.000-08:00

Things To Do In Quartzsite
2008 - 2009

http://www.quartzsitetourism.us/showschedule.htm

http://www.quartzsitetourism.us/calendar.htm

RICE RANCH ROUNDUP [Vendor List]
928.927.8118
NOVEMBER 1, 2008 - FEBRUARY 28, 2009
DESERT GARDENS 8TH ANNUAL
INTERNATIONAL
GEM, MINERAL & JEWELRY SHOW
JANUARY 1 - FEBRUARY 28, 2009
Hi JOLLY DAYS PARADE
928.927-6159
January 3, 2009
Hi Ali Swap Meet
November 1, 2008 - February 28, 2009

MAIN STREET TRADERS
Open Year Round!
November 1, 2008 - February 28, 2009

TYSON WELLS SELLARAMA [TYSON WELLS MAIN SITE]
928.927.6364
JANUARY 10 - JANUARY 25, 2009

"It's Chili in Quartzsite"
Chili Cook-off & State Salsa Championship
Men's & Women's Open at Tyson Wells
February 28, 2009
BLUEGRASS FESTIVAL - Tyson Wells Showgrounds
February 27 - March 1, 2009
ROCK AND GEM MINERAL SHOW JANUARY 2-11, 2009
SELL-A-RAMA JANUARY 10-25, 2009
ARTS & CRAFTS FAIR JANUARY 30 - FEBRUARY 8, 2009
THE MAIN EVENT
January 10, 2009 - January 25, 2009

BIG TENT EVENTS [Vendor Links]
1.800.969.5464
SPORTS & VACATION & RV JAN 16-25, 2009
HOBBY, CRAFT AND GEM SHOW
JANUARY 28 - FEBRUARY 1, 2009
ROCK & ROLL CLASSIC CAR SHOW January 31 - FEBRUARY 1, 2009

PROSPECTOR'S PANORAMA
November 1, 2008 - February 15, 2009
928.927.6467
43RD ANNUAL QIA POW WOW [Vendor List]
928.927.6325
JANUARY 21 - 25, 2009
QUARTZSITEIMPROVEMENTASSOC.COM
HIT AND MISS ENGINE
JANUARY 23-25, 2009
FEBRUARY:
ATV Record Attempt Parade
February 7, 2009
Quartzsite Quilters Quilt Show
Senior Center 928-927-6496
February 14, 2009

February 27- March 1, 2009 Blue Grass Festival at Tyson Wells

February 28, 2009 Chili Cook-Off & State Salsa Championship

Hotels/Motels

There is one motel in Quartzsite with online reservations - Super 8 Motel
(Rates, availability and reservations online)

There are other hotels and motels in nearby (about 20 miles) Blythe, CA and one in Ehrenberg CA (Rates, availability and reservations online)

For reservations in, Indio CA - Yuma AZ or Lake Havasu.
(Rates, availability and reservations online)

Camping & RV Parks

There are camping and a plethora of RV accommodations in and around Quartzsite. For more information, contact:

* Quartzsite Chamber of Commerce
495 Main Event Lane
Quartzsite, Arizona 85346
928-927-5600

* Arizona State Parks 602-542-4174
* Arizona National Forests 800-280-CAMP

November 2008 Mineral of the Month: MALACHITE

2008-10-23T19:35:00.000-07:00

Hello All Del-Airs and Interested Guests!

Welcome to the online version of our November 2008 Mineral of the Month:

MALACHITE

Malachite is a green mineral with a widely variable habit. Typically it is found as crystalline aggregates or crusts, often banded in appearance, like agates. It is also often found as botryoidal clusters of radiating crystals and as stalactitic aggregates as well. Single crystals and clusters of distinguishable crystals are very uncommon, but when found, they are typically acicular to prismatic. It is found in the oxidized regions of copper deposits. It is also frequently found as a pseudomorph after Azurite crystals. It's chemical properities are as follows:

Crystal Structure: Monoclinic; Mineral Group: Carbonates; Chemical Formula: Cu2[(OH)2ICO3]; Specific Gravity: 4.0; Tenacity: Brittle; Color: Rich Green; Hardness: 3-1/2 to 4; Luster: Adamantine/Vitreous on Crystal Faces. Silky on Fibrous & Botryoidal Habits; Transparency: Translucent to Opaque; Streak: Pale Green; Cleavage: Perfect; Fracture: Irregular/Uneven, Sub-Conchoidal, Fibrous

October 2008 Mineral of the Month

2008-09-24T19:36:00.000-07:00

October 2008 Mineral of the Month:

Barite

Named from the Greek word βάρος, meaning weight, due to its unusual heaviness for a non-metallic mineral. Barite forms as tabular and prismatic crystals which can be very large. It also forms as small sand bearing rose shaped concretions called desert roses. Other habits are granular, fibrous, cockscomb, or columnar. It forms in hydrothermal veins with a number of other minerals including quartz, calcite, fluorite, galena and many others. Barite also forms in clay nodules, in veins of sedimentary strata and around hot springs. It is insoluble in acids and some varieties are fluorescent.

Its chemical properties are as follows:

Crystal Structure…Orthorhombic
Mineral Group...Sulfates

Chemical formula...BaSO4)

Specific Gravity...4.5

Tenacity…Brittle

Color...Colorless, White, Gray, Red, Green, Brown, Blue, Yellow

Hardness...3 to 3-1/2
Luster...Vitreous, Resinous or Pearly
Transparency...Transparent to Translucent
Streak…White
Cleavage...Perfect
Fracture…Uneven

Tri-Fecta At The Antelope Valley Fair

2008-08-26T23:14:00.000-07:00

Kudos' to Del Air members Richard Haering, Chris Ward and Bob Knox for continuing their first place winning streak with their display cases at the 70th Annual Antelope Valley Fair.

This is Richard Haering's first year submitting a competitive case. His display of metamorphic rock slices has won first place in both the CFMS and Antelope Valley Fair shows. Way to go Richard!!! In addition to winning the first place prize in each of their respective classes, Chris Ward was also awarded the "Judges Choice" prize for his display of world-wide geodes and Bob Knox walked off with the esteemed "Best in Show" prize for his display of incredible Stromatolites.

We also have our Del Air club case on display as well.

The fair is open daily and runs thru Monday September 1st, 2008. I encourage all to attend if you can. It is a lot of fun and educational as well.

See You All At The September Meeting!!

August/September 2008 Mineral of the Month

2008-08-26T22:09:00.000-07:00

August/September 2008 Mineral of the Month:

Quartz

Quartz is the most common mineral found on the surface of the Earth. A significant component of many igneous, metamorphic and sedimentary rocks, this natural form of silicon dioxide is found in an impressive range of varieties and colors. There are many names for different varieties: Crypto-crystalline varieties of Quartz are called Chalcedony and include the Agate family. Quartz can also be found in other forms such as Petrified Wood and Jasper.

Its chemical properties are as follows:

Crystal Structure…Trigonal

Mineral Group...Oxides

Chemical formula... SiO₂

Specific Gravity...2.65

Tenacity…Brittle

Color...Colorless, Purple, Rose, Black, Yellow, Brown, Green, Orange, etc.

Hardness...7
Luster...Vitreous
Transparency...Transparent to Translucent
Streak…White
Cleavage...Poor/Indistinct
Fracture…Conchoidal

Prasiolite, Tigers Eye, Citrine and Onyx are also forms of Quartz. Pure quartz is colorless or white; colored varieties include rose quartz, amethyst, smoky quartz, milky quartz, and others. The most important distinction between the types of quartz is that of macro-crystalline (individual crystals visible to the unaided eye) and the crypto-crystalline varieties (aggregates of crystals visible only under high magnification). Chalcedony is a generic term for crypto-crystalline quartz. The crypto-crystalline varieties are either translucent or mostly opaque, while the transparent varieties tend to be macro-crystalline. Although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral. Color is a secondary identifier for the crypto-crystalline minerals, although it is a primary identifier for the macro-crystalline varieties. However this does not always hold true.

Antelope Valley Fair

2008-08-11T19:35:00.000-07:00

To All Del Air Members and Interested Guests:

This is a reminder that myself, Bob Knox and Richard Haering will be entering 4 competitive cases in the Antelope Valley Fair this year. One of these cases will be a club case and this will be the first time that the Del Air's have been represented at this fair. This is the 70th Annual celebration of this fair and I have been a competitive displayer here for the past four years. I encourage all to attend as I feel it is the best fair around. Smaller than the LA County Fair and larger than the Ventura County Fair, the Antelope Valley fair has something for everyone.

I realize everyone must thinking its too hot or too far away but it really is no farther than the Ventura fair and to beat the heat, each year, I arrive around 5:30 pm as the fair is open till midnight. I first check out all the attractions and displays in the air conditioned buildings and by the time I am through, the sun has gone down and the breeze has kicked in and the desert evening turns out to be quite enjoyable and comfortable.

The fair is located at the new Antelope Valley Fairgrounds:
2551 West Avenue H, Lancaster, CA 93536
661-948-6060
Take the I-14 freeway north to Avenue H exit and turn left. You can't miss it.

The Antelope Valley Fair is open this year from Friday August 22nd through Monday September 1st 2008. They are open from 12 noon till midnight on the weekends and from 4:00 pm till midnight midweek.

Admission is:
$8.00 for adults 12 yrs and older
$5.00 for juniors 6 to 11 yrs and seniors 62 yrs and above
$Free for children under 6 with paid adult and for active military with military ID

Parking is $5.00

So join us at the fair and check out our Rock and Gem exhibits as well as everything else the fair has to offer. Hope to see you there!!

CORRECTION TO THE GARAGE SALE DATES

2008-08-11T19:28:00.000-07:00

Thanks to our very own eagle eyed Del Air member, Ethel Hellenthal , it has been brought to my attention that I listed the tentative date for the upcoming annual Del Air garage sale incorrectly. The correct tentative date is Saturday September 20th, 2008. I originally posted the date as being in November. I apologize for this error and hope you all will forgive me! If you scroll down to that post you will see that it has been corrected.

Your humble blogger,
Chris.

August /September 2008 Mineral of the Month

2008-08-07T21:40:00.000-07:00

Just because the Del Airs do not have any regularly scheduled meetings during the month of August doesn't mean we have forgotten the Mineral of the Month!

This new club feature has proven to be such a hit each month that we have decided to do a double presentation at our September 4th 2008 meeting.

The featured mineral will be........'Quartz'.........in all its spectacular forms and brilliant colors and exotic crystal shapes. Amethyst, Citrine, Jasper, Agate, Chalcedony, etc, etc, etc,

There will be a double sided full color handout for all to take home. As always, we encourage all attendees to bring their most prized quartz specimens to the September 4th 2008 meeting to share with the club. Lets make this our biggest turnout yet.

So keep an eye on our blog. Coming soon.....to a PC or laptop near you.....

The August/September 2008 Mineral of the Month.....'Quartz'

Annual Del Air Rockhounds Garage Sale and Grab Bag Stuffing Extravaganza

2008-08-07T21:08:00.000-07:00

Attention all Del Air Members and Interested Guests:

First, the garage sale....

Just a heads up to let you all know we have tentatively scheduled our annual garage sale for Saturday September 20th 2008 starting @ 9:00 am to be held at Bob Backus's home. Should this change for any reason a new post will be sent to all.

If you have anything you'd like to donate to the sale or if you'd like to donate your time and help out during the sale please contact Bob Backus (his contact information can be found in the monthly bulletin) or you can e-mail me @ chris_ward678@yahoo.com and I will respond with the appropriate information.

All proceeds go to the Del Air Rockhounds and help to bring us closer to obtaining our own shop.

Second, the Grab Bag Stuffing Extravaganza.....

Bob and Maxine Dearborn will be hosting a grab bag stuffing at their home tentatively scheduled for Saturday November 8th 2008 at 10:00 am. Again, should this change a new post will be sent to all.

We have gone thru almost all of our inventory of grab bags. As you may or may not know, the grab bags are the number one selling item at our annual show as well as the many school fairs our club is involved with each year. Our show is quickly approaching and we need to replenish our stock. Should you care to volunteer your time, usually 2 or 3 hours, please contact Bob or Maxine (their contact information can also be found in the monthly bulletin ) or e-mail me at the above listed e-mail address and I will respond appropriately.

Thank you all in advance for your participation and support.

Information On DEL AIR Education Team

2008-08-07T19:39:00.000-07:00

The Del Air Rockhounds Presents............

"ROCKS IN YOUR CLASSROOM"

Click this link and you can have
our Voice Line call you back
on YOUR Phone!

Del Air Rockhounds club members can visit your classroom with a presentation on geology and the earth sciences. Our education outreach committee offers a variety of classroom programs.

Introduction to Geology (4th grade curriculum) Interactive Discussion / Slide Show / Hands-on Specimens

Students will have a chance to hold a variety of rocks and fossils in their own hands!
Program is 50 minutes to an hour depending on age level

Introduction to Fossils (2nd grade curriculum) Interactive Discussion / Hands-on Specimens / Project Stations

Students will have the chance to hold many types of fossils in their own hands such as Petrification, Trace, Amber, and Frozen fossils.
Program is 40 minutes to an hour depending on age level.

To schedule you school visit contact:
Del Air Member Maxine Dearborn at our
Voice Mail: (818) 714-0321

Programs are free of charge! (nominal transportation fee outside of the San Fernando Valley)

Donations may be given to Del Air Rockhounds Club.

Please scroll down to see what some of our star students have to say about our "Rocks in Your Classroom" presentations.......

2008 C.F.M.S. Show Report

2008-07-02T20:45:00.000-07:00

Greetings to all Del Air members and interested guests!

It turned out to be a banner year for Del Air members at the 2008 C.F.M.S show at the Ventura County Fairgrounds this past weekend. Member Richard Haering took the Blue Ribbon First Place Award in the novice category for his exemplary display of Australian Metamorphic Rock.

Del Air's very own treasurer, Bob Knox, took First Place in the advanced fossils category and was awarded the Blue Ribbon and a plaque for his wonderful collection of Stromatolites.

And finally, your humble blogger himself, Chris Ward, took the First Place Blue Ribbon and a plaque for my dispaly of Fortification Agates.

We also displayed a Del Air Club Case at the show. The club cases were for display only and not in a judging category, but if they were, I bet we would have taken a First Place Blue Ribbon for this case as well.

The three of us attended the awards banquet on Saturday night after the show closed for the day. We had a delicious prime rib dinner with garden vegetables and roasted baby red potatoes with rosemary. Cheesecake and coffee was served for dessert and good time was had by all those in attendance. We made many new friends and got reaquainted with some old ones.

The weather was incredible with highs in the upper 70's and a cool and refreshing ocean breeze. Foot traffic was much improved over last years show in Lancaster. We volunteered to work in the kids booth on Sunday manning the Spin-a-Wheel, sand sifting for treasure, paint a fossil dinosaur bone and other fun games for the kids. We ran into Del Air members Bob and Maxine Dearborn who showed up on Saturday and also volunteered to work in the kids booth. We saw Jason Badgely, Oscar and Julie Marin and Bob, Leilani, and Jamie Backus as well.

Our heartfelt thanks to those who were able to come out and support the Del-Air's in their quest for victory. And a very special thank you to Bob Backus for his amazing carpentry work on the cases. It took a lot of planning and some good old fashioned knuckle busting to pull off four cases for this show but it was worth every effort and speaking on behalf of all three of us, we are already planning for next years C.F.M.S. show in San Jose. Del Air's ROCK!!

See you all at the July 10th meeting.

Chris, Richard and Bob

July 2008 Mineral of the Month: Gypsum

2008-07-02T19:52:00.000-07:00

July 2008 Mineral of the Month

Gypsum

Named in antiquity from the Greek word "gypsos," meaning plaster. It can be found as a massive material including the Alabaster variety and also as clear crystals in the Selenite variety. It can also form as a parallel fibrous growth known as the Satin Spar variety. Commonest of the sulphate minerals, gypsum is found in marine evaporates, in caves where the air is dry enough to allow it to be deposited and remain, at fumaroles, and, on occasion, in the oxidized zones of sulfide deposits. Crystals are tabular and diamond shaped. Rosette shaped masses are known as Desert Roses and radiating forms are termed Daisy Gypsum.

Its chemical properties are as follows:

Crystal Structure…Monoclinic
Mineral Group...Sulfates
Chemical formula...Ca(SO4) . 2H2O
Specific Gravity...2.32
Tenacity…Brittle
Color...Colorless, White, Gray, Reddish, Greenish, Brownish, Yellowish
Hardness...2
Luster...Vitreous (Pearly on cleavage)
Transparency...Transparent to Opaque
Streak...White
Cleavage...Perfect
Fracture...Splintery

Because You Asked

2008-06-20T21:26:00.000-07:00

Del Air member Dodd Roth asks:

Do you know of any gypsum mines that have colored rocks?

"Because You Asked" answers:

None that I know of personally, however, there are literally thousands of gypsum deposits around the world...stretching from Antarctica to the Siberian Steeps. Few are mined for anything other than industrial purposes but some collector specimens seem to be collected at a high percentage of them. Though the crystals are colorless to white, many deposits will have mineral associations that can color gypsum in an assortment of shades depending on what the associated minerals are. Mindat.org has a large gallery of gypsum photos from almost 100 locations that show several different colors. Massive forms (lapidary rough) of gypsum can also have a lot of color variation, probably more so than that of crystals. I do not know and can not find a list of commercial gypsum "lapidary material" locations, but If such a list exists it would most likely be a long one.

Thanks for asking!!

"BECAUSE YOU ASKED"

2008-06-15T18:11:00.000-07:00

Del-Air guest attendee, Richard Leyton, asks:

I am looking forward to going on the Mt. Gleason field trip on June 21st. The bulletin says to bring light digging tools. What does that mean? A prospector's pick? A gardening trowel? A 6 foot shovel? A full size pick ax?

Thanks, Richard Leyton

'Because You Asked' answers:

Light digging tools would refer to rock hammers, chisels, small garden trowels, crow bars etc. Basically hand sized tools. Also a spray bottle filled with ordinary water to spritz down your specimens to better identify what you are bringing home. Bring a pair of safety goggles to protect your eyes when hammering rocks. I carry one of each of these hand sized tools in a canvas tote bag with handles whenever I go rock hounding. The bag is large enough to hold the rocks I want to bring back as well. A heavy duty back-pack would work too.

Heavy digging tools would refer to full size pick-axes, sledge hammers, full size shovels and industrial size pry bars. These, however, are much more unwieldy and are difficult to lug around especially whens it really hot.

Don't forget to bring food and plenty of drinking water so you stay hydrated. Watch out for snakes and keep an emergency first aid kit in the car.

I hope this answers your question and provides you with a few tips as well.

Till next time...........Happy Rock Hounding!!!

"Because You Asked"

2008-06-12T20:23:00.000-07:00

June's mineral of the month, Calcite, elicited a fair amount of oohs and aahs, as members and guests had an opportunity to examine the several beautiful and extremely different examples of this relatively common mineral. Hopefully this new feature of the Del-Air Rockhounds Club is being enjoyed and we are all learning something new.

This brings us to yet another new feature of the club, "Because You Asked". If anyone ever has a question regarding rocks, minerals or other rock hounding subjects that can not be answered while at our monthly meetings, simply e-mail your question to Bob Knox at: rknox1@socal.rr.com or Chris Ward at: chris_ward678@yahoo.com and your query will be researched and answered right here in your blog. Questions may be submitted at any time and members and interested guests will receive an e-mail notification stating the answers have been posted to the blog.

And now....for our first question....

Mrs. Paul O'Connor asks...."In the information handout for the June 2008 Mineral of the Month, Calcite, the word 'gangue' appeared in the mineral's description. What does this word mean?

"Because You Asked" answers:

Ore and Gangue: The general definition of “ore” is a naturally occurring material from which minerals of economic value can be extracted at a profit. For example “gold ore” or “iron ore”. Ore minerals are the specific minerals containing the commodity of interest. Many minerals contain elements of commercial interest, but are not ore minerals because the mineral is “refractory”, meaning it is difficult or impossible to extract the commodity from the mineral. Gangue (pronounced like 'gang') minerals refer to the material so intimately associated with the ore that it has to be mined along with the ore and is later removed by various crushing, grinding and separation processes. The “host rock” is the rock surrounding the ore and gangue, which has no value. To illustrate these relationships, consider the following example for a gold ore:

A gold-bearing quartz vein 1 foot thick occurs in a granite intrusion. The quartz vein contains arsenopyrite and pyrite in addition to native gold. The “ore” in this example is the quartz vein that contains concentrations of gold. The ore mineral is the native gold. The gangue minerals are quartz, arsenopyrite and pyrite. The granite is the host rock.

Thanks for the questions and keep them coming!!

Del Air Rockhounds Present............

2008-05-26T19:38:00.000-07:00

June 2008 Mineral of the Month

Calcite

Found in most geologic settings and, in one form or another, as a later forming replacement mineral in many other environments . It is most common as a massive material in limestones and marbles. It forms as chemical sedimentary deposits in limestone and can be regionally metamorphosed into marbles. Calcite is also a common gangue mineral in hydrothermal deposits. Its crystals are rhombohedral and scalenohedral with combinations producing “nailhead” and “dogtooth” forms. Iceland Spar variety shows double refraction. Twinning is very common.

Its chemical properties are as follows:

Mineral Group......................Carbonates
Chemical formula................CaCO3
Specific Gravity...................2.71
Tenacity…………………….Brittle
Color......................................White, Yellow, Red, Orange, Blue, Green, Brown, and Grey
Hardness..............................3
Luster....................................Vitreous, Pearly
Transparency.....................Transparent to Translucent
Streak....................................White to Greyish
Cleavage..............................Perfect
Fracture...............................Subconchoidal

Del Airs Prove To Be Most Popular Once Again!!

2008-05-12T19:03:00.000-07:00

The Del Air Rockhounds booth once again proved to be the most popular attraction at the Our Community Charter School's Spring Fair. The day was sunny and bright and not too hot with a nice cool breeze blowing all day long. Del Air members showed up in force to help man the booth. A big and hearty THANK YOU goes out to Bob & Maxine Dearborn, Julie & Oscar Marin, Hiro Matsuo, Len & Ethel Hellenthal, Jeff Dengrove, Bob Knox and Chris Ward. A very special THANK YOU goes out to Ben Fullon and Richard Quezada, two potential new Del Air members, who sacrificed their time to help us out on this event. Ben spent the entire day manning the "What Is It" table helping youngsters and grown-ups alike identify the many amazing rocks we had on display. Richard wasted no time getting down and dirty with the tile saw and in no time was quickly slicing open geodes like a pro. Their participation is greatly appreciated.

As always, the "Spin-a-Wheel", manned by Ethel, Len and Hiro attracted quite a few people as well as the "Paint Your Own Dinosaur Claw" table expertly handled by Julie, Oscar and Maxine. Bob Knox lent a hand wherever and whenever it was needed. Myself, Jeff, Bob Dearborn and Richard worked the geode cutting table. We all had a blast and ended up raising a goodly amount of money for both the school and our club as well.

Del Airs to Appear at Woodland Hills Library

2008-05-12T18:42:00.000-07:00

Hello to all Del Airs and Interested Guests!

It has been brought to my attention that the Del Air Education Team will be making a special presentation at the Woodland Hills Branch Library located at:

22200 Ventura Blvd
Woodland Hills, CA 91364
(818) 226-0017

The presentation is entitled: "REALLY? IT'S A DINOSAUR!"
Saturday May 17th, 2008 at 11:00 am

It it or isn't it a dinosaur? There are all kinds of fossils; only some are from dinosaurs.

Join the members of the Del Air Rockhounds as we teach how to identify dinosaur fossils. We will also offer aid in identifying rocks and fossils for those who choose to bring them along.

Please pass this information along to all your friends and family members and encourage them to show up and witness our outstanding education team in action. They truly are the best.

Daily News Press Release on Del Air Education Team

2008-04-17T19:15:00.000-07:00

Attn: Del Airs and Interested Guests,

Please scroll down for a press release that appeared in the Daily News on April 12, and was contributed by our very own Julie Marin. It's things like this that keeps our club in the community spotlight. (Great job Julie, you're the BOMB!!!!)

-------------------------------------------------------------------------------------------------

"Jim Van Winkle and Dick Flaharty give hands-on instruction to students at Capistrano Street Elementary School."

Provided by: Julia Marin

This team is certainly not nearly as well known as the Dodgers, the Lakers or even the local high school teams. This team is the Del Air Rockhounds Education Team and it's all about education.

The six-member team, led by Maxine Dearborn, is fast becoming quite well known among teachers and students of second and fourth-grade classes in the Valley.

The Del Air Rockhounds Club is a 501(c)(3) nonprofit organization. The Education Team members are volunteers who donate their time to introduce students to the beauty and wonder of rocks and their formation, as well as many types of fossils.

The students get to view up-close the many exhibits such as a tooth from a mammoth, a replica of a sabre-tooth cat and petrified dinosaur dung. They get to ask questions and have hands-on experiences they might not otherwise have.

In just three months (February-April), the team will have visited 15 public and private schools in the Valley, teaching the students about the earth sciences. By the end of April, team members will have spoken to more than 2,000 students.

Capistrano Street School PTA invited the team to present its program to the entire school. The team spoke to more than 400 students in two days and scored big with the grade-school audience.

The Del Air Rockhounds Club does not charge for the school presentations, however, donations are gratefully accepted. A recent donation enabled the team to purchase several magnifying glasses for the students to use, making the exhibit an even more hands-on experience for future classes.

Anyone interested in learning more about the club is invited to attend a meeting at 7:30 p.m. the first Thursday of each month at the United Methodist Church of Northridge, 9650 Reseda Blvd, Northridge CA.

Please visit www.delairrockhounds.blogspot.com or e-mail DelAirRockhounds@gmail.com.

Del Air Rockhounds Spring School Fair Booth

2008-04-16T22:16:00.000-07:00

Hello Again All Del Airs & Interested Guests,

Announcing: The Del Air Rockhounds Booth at the Our Community Charter School Spring Fair.

Date: April 26th 2008
Time: 9:30 am to 2:00 pm (set-up starts @ 9:00am)
Where: Our Community Charter School
16514 Nordhoff St.
North Hills, CA 91343

This is a school fair our club has been attending for the past 5 to 6 years now and they want us back again this year! We set up our booth and talk to kids and their parents about our hobby. We set up an educational table with touch and feel exhibits. We run our ever popular Spin-a-Wheel game, sell grab bags and cut geodes.

We will need a minmum of 6 members at all times to run this booth. This event proves to be very good for our treasury. It is also a lot of fun and as an added extra bonus it allows us to spread the word and spark an interest in rocks and minerals to the many people who will be visiting our booth. We are by far the most popular booth at this event each and every year.

As a special note to potential new members, this would be the perfect event to volunteer for as your participation is taken into account when the club members vote on new member acceptance. If you can spare the time just show up at the school at 9:00 am on Saturday April 26th and we'll find something for you to do.

May 2008 Mineral of the Month 'Fluorite'

2008-04-16T19:31:00.000-07:00

May 2008 Mineral of the Month
Fluorite

From the Latin word ‘fluere” meaning ‘to flow’. The crystals formed by this mineral are cubic and octahedral in shape and are often twinned. Fluorite may also form in massive, granular and compact habits. It occurs in a great variety of colors, ranging from purple, green, colorless, white and yellow to pink, red, blue and even black. Fluorite forms in hydrothermal veins, especially those containing lead and zinc and also around hot springs. Fluorite is a fairly common mineral found all over the world and is associated with quartz, calcite, dolomite, galena, pyrite, chalcopyrite, sphalerite, barite, and various other hydrothermal-vein minerals. As its name suggests, it can be highly fluorescent in ultraviolet light.

Its chemical properties are as follows:

Mineral Group.....................Halides
Chemical formula..............CaF2
Specific Gravity..................3.1 to 3.3
Tenacity…………………...Brittle
Color.....................................Multiple
Hardness.............................4
Luster...................................Vitreous
Transparency....................Transparent to Translucent
Streak..................................White
Cleavage.............................Perfect Octahedral
Fracture...............................Conchoidal

Del Air's new "Mineral of the Month" feature.

2008-03-28T18:36:00.000-07:00

The Del Air Rockhounds Club is proud to present to it's members and all interested guests, a brand new feature of the club.....Drum roll please........."The Del Air Mineral of the Month". Beginning in April of this year, we will be presenting a different featured mineral each month. A detailed description along with photos will be presented here on your blog as well as in the bulletin each month. There will also be a brief educational presentation at each months general meeting along with a color handout detailing the featured mineral. All members and guests are encouraged to bring specimens of the featured mineral from their own collections in order to help demonstrate visual differences such as shape, color, crystal structure and so on. (Don't worry....you won't have to speak in front of the crowd if you bring in a specimen....unless, of course you want to.) So make sure you read your bulletins and check out the blog each month so you will be able to bring in your versions of the featured mineral. The write up was not completed in time to make it into the April bulletin so I will e-mail the blog to all members. Bob Dearborn has already given you all a brief heads-up via e-mail.

So without further ado.....Del Air Rockhounds Club proudly presents our very first "Mineral of the Month" for April 2008

"P Y R I T E"

Named in antiquity from the Greek word "pyros" meaning "fire" because of the sparks coming from it when struck with another mineral or metal object. Pyrite is a very common mineral, found in a wide variety of geologic formations, from sedimentary deposits to hydrothermal veins and as a constituent of many metamorphic rocks. Commonly called "fool's gold" due its brassy-yellow color but it is much less dense (lighter) but harder than gold and cannot be scratched by a fingernail or knife. This mineral forms as cubic, pyritohedral, or octahedral crystals. Twinning is common. The crystal faces are striated. Pyrite can be massive, granular, reniform, stalactitic, botryoidal and modular. Fine crystals often occur with sphalerite and other sulfides.

Its chemical properties are as follows:

Mineral Group......................Sulfides

Chemical formula................FeS2
Crystal system.....................Isometric
Color....................................Brassy-yellow
Hardness.............................6 to 6 &1/2
Luster...................................Metallic
Transparency......................Opaque
Streak..................................Greenish-black
Tenacity...............................Brittle
Cleavage.............................Poor/indistinct
Fracture...............................Irregular/uneven, conchoidal