Although most gemstones are mineral materials, a number of organic materials and fossilized organisms are considered to be gemstones. The most common of these are pearl, bone, amber, coral, ivory, petrified wood, fossil coral, dinosaur bone and more.
Chrysoberyl is an extreme gem. At 8.5 on the Mohs Scale it is the third hardest gem mineral. At 3.7 to 3.8 it has a very high specific gravity for a non-metallic mineral. It is the gem with the finest cat’s eye. And, some specimens change color depending upon the type of incident light.
An interesting article on “Diamonds and the Geology of Mantle Carbon” that considers the various types of diamonds, their host rocks, inclusions, geographic distribution, environments of formation, age, trace element composition, textures, carbon/nitrogen isotopes, geobarometry, and lots more.
The Arizona Geological Survey just published a special episode of Arizona Mining Review. Lee Allison interviews Peter Megaw, Exhibits Chair of The 60th Annual Tucson Gem and Mineral Show which begins today. At least 40 other gem, mineral, fossil and jewelry shows have been occurring in Tucson for the past few weeks.
A few companies are producing “memorial diamonds” from the remains of cremated humans. For a few thousand dollars you can have a 1/4 carat (about 4 mm) diamond produced after your death for your heirs.
Ammolite is a trade name given to a thin iridescent aragonite shell material that is found on two species of extinct ammonite fossils (Placenticeras meeki and Placenticeras intercalare). Gem-quality Ammolite produces a spectacular display of iridescent color when it is observed in reflected light. The colors of an individual stone can run the full range of the visible spectrum or be limited to just one or two colors. The color display can rival fine opal and labradorite in its intensity and beauty.
They are called “anthill garnets” because they are found on and around the margins of anthills. The ants encounter the garnets while excavating their underground passages, haul them to the surface and discard them.
““Iris Agate” is a name used for a finely-banded agate that produces a spectacular display of color when it is cut properly and illuminated from a direction that sends light through its very thin bands.”
Labradorite is a feldspar mineral of the plagioclase series. Some specimens exhibit a schiller effect, which is a strong play of iridescent blue, green, red, orange, and yellow colors. Labradorite is so well known for these spectacular displays of color that the phenomenon is known as “labradorescence.”
Alrosa, the state-controlled diamond mining company of Russia, reports that they have found a 235 carat gem-quality diamond at their Yakutia mine in Siberia. The stone is valued at $1.5 to $2 million US.
Few people think of Brazil as a source of diamonds, but in the 1700s the country was the world’s leading supplier of gem-quality diamonds. Production continues there today with about 25,000 carats produced per year.
Russia is currently the world’s second largest producer of gem-quality diamonds, after Botswana. Alrosa, Russia’s largest diamond producer, has plans to surpass the production of DeBeers, the world’s leading diamond-producing company, by 2018. Their success may help Russia become the world’s leading diamond producing nation.
“A seven-hour flight from Moscow to the small town of Mirny, followed by another two-hour helicopter ride brought me to one of the most remote regions on earth, where many of the world’s diamonds are mined, Alrosa’s Nyurba mine in the Republic of Yakutia.” Quoted from the Botswana Diamond Manufacturers Association press release.
Fluorite is an important industrial mineral used in a variety of chemical, ceramic and metallurgical processes. Although the United States has some fluorite deposits, most of the mineral consumed here is imported from China, Mexico, Mongolia and South Africa.
The-Vug.com has a large list of mineral shows that will be held in the United States and throughout the world. There is probably one happening near you!
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