January 2011 Fossil of the Month

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

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!

Please support the Rock Chippers and attend their show.

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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

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September 2010 Mineral of the Month

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