COPPER - An ore & gemstone

I wrote a few books about copper and found every time a company (or myself) discovered a new copper deposit, the US Forest Service was there to withdraw large areas of public land to keep companies and individuals from mining, even though they had a legal right under the 1872 mining law.  

Two books of mine that I recommend include (1) Hausel (1997), The Geology of Wyoming's Copper, Lead, Zinc, Molybdenum and Associated Metal Deposits in Wyoming: Geological Survey of Wyoming Bulletin 70, 224 p., and (2) Hausel (2009), Gems, Minerals and Rocks of Wyoming. A Guide for Rock Hounds, Prospectors & Collectors. Booksurge, 175 p. In Wyoming, I found some very nice copper specimens at the Charter Oak mine and the Kurtz Chatterton mine in particular. There were many others, but these two mines seemed to be standouts.

 Wyoming malachite above fills vugs with tiny prismatic crystals that are enclosed by tawny limontie.

Copper yields a large number of minerals and some can be used as gemstones. The more prominent used for gems include turquoise and chrysocolla because of their superior hardness compared to many of the other copper minerals. Now that I'm in Arizona, I'm finding there are many extraordinary copper minerals all over the southern half of the state. The photo in the upper left is a boulder of azurite (blue), tenorite (black) and minor malachite (green) from the Morenci Arizona area. Imagine wearing that as a pendant around your neck. Maybe a bit heavy.

Although azurite (H=3.5 to 4), malachite (H=3.5 to 4), and tenorite (H=3 to 4) can produce extraordinarily specimens due to their vivid color, their poor hardness precludes much use of these of gemstones because they are so easily scratched.

 Cuprite (red) with malachite (green) and tenorite (black) from the Seminoe Mountains, Wyoming.