October 2008 Mineral of the Month

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

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

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

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

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.