Image: House Resources Committee |
Small quantities of gemstones are produced in several US states. Notable quantities of beryl, coral, garnet, gem feldspar, opal, quartz, sapphire, ruby, shell, pearls, topaz, tourmaline and turquoise are currently produced. According to the United States Geological Survey's Minerals Yearbook, eight states were responsible for most of the US production during calendar year 2004. These eight states with the highest dollar value of production are summarized below.
- Tennessee
- Arizona
- Oregon
- California
- Idaho
- Montana
- Arkansas
- Nevada
Tennessee Gemstones
Tennessee leads the United States in gemstone production based upon total value. There, The American Pearl Company operates the only
freshwater pearl farm in the United States. Two companies, The American Shell Company and Tennessee Shell Company harvest
mollusk shells from the Tennessee River. These shells are crushed and sold as seed material to the cultured pearl industry.
Arizona Gemstones
Arizona is the second-place state for gemstone production.
Peridot and
turquoise are the leading gemstone products, however, notable amounts of
agate,
jasper,
petrified wood,
garnet and
opal have been produced. Arizona has been a world leader in the production of gem quality peridot, mostly from the Peridot Mesa and Buell Park areas. Turquoise is Arizona's most important gemstone by value of production and Arizona turquoise is world famous in the market. Most of the turquoise is produced as a by-product of copper mining. Some of the turquoise is produced as a continuous mining effort and some is produced as it is uncovered during the mining cycle. Production is labor intensive because careful hand extraction is required. Arizona agates, jaspers and petrified wood are used to produce a very wide range of products which include tumbled stones, cabochons, polished pen and pencil set bases, clock faces, bookends, carvings, and more.
Oregon Gemstones
Oregon produces some of the best gem-quality
feldspar in the world.
Red labradorite, also known as
sunstone or
heliolite, is one of Oregon's most popular gems. Sunstone is a labradorite that contains large numbers of microscopic copper platelets that are suspended in alignment throughout the stone. These platelets strongly reflect light that is incident from specific directions. This reflection yields a golden-red play of color. Sunstone occurs in a variety of colors which include yellow, clear, pink, red, salmon, green and blue-green. The sunstones are found in certain basalt flows which have large feldspar phenocrysts. The method of production is labor intensive. They are screened by hand from soils which have formed above the basalts. Attempts to mine the unweathered basalt flows result in shattered sunstones. In addition to sunstone, Oregon produces a variety of different
agates, jaspers and obsidians.
Of particular note are the very popular "
thundereggs". These nodules or
geodes which form in rhyolites, welded tuffs or perlites, are not very impressive on the outside. However when they are cut open they frequently contain layered or fortification patterns of colorful chalcedony, sometimes with a drusy quartz-lined inner cavity. Many people believe that they are Oregon's most popular gemstone.
California Gemstones
California produces a wide variety of gemstones but is especially known for its
tourmaline and
turquoise. Native Americans treasured tourmaline crystals and a commercial industry had developed by the late 1800s. The tourmaline deposits of Riverdale and San Diego Counties have yielded more gemstones and specimens than any other deposits in the northern hemisphere. California tourmalines occur in a wide variety of colors with the typical greens and pinks produced in good quantity. Bicolor and tricolor stones from both lateral and concentric crystal zonation are also produced. These stones are used for faceting, carving, cabochons and specimens.
The production of turquoise has a long history in California, beginning with the pre-Colombian Native Americans in the area that is now San Bernardino County. Turquoise nodules and vein fillings have been produced from deposits in San Bernardino, Imperial and Inyo Counties, however, nearly all of those deposits are no longer active.
U.S. Gemstone Production
Values in Thousands of Dollars |
Gem Material | 2003 | 2004 |
Beryl | 18 | 18 |
Coral | 118 | 261 |
Garnet | 56 | 207 |
Gem Feldspar | 659 | 659 |
Geode / Nodules | ND | ND |
Opal | ND | ND |
Quartz - Microcrystalline | 228 | 206 |
Quartz - Cryptocrystalline | 391 | 383 |
Sapphire / Ruby | 474 | 473 |
Shell / Freshwater Pearls | 2490 | 4000 |
Topaz | ND | ND |
Tourmaline | 48 | 45 |
Turquoise | 827 | 699 |
Other | 6870 | 7160 |
Totals | 12500 | 14500 |
ND - value not disclosed because it would reveal proprietary information of a small number of producers - included in totals. |
Idaho Gemstones
Idaho produces relatively small quantities of many different gemstones.
Agates and
jaspers are produced from deposits scattered across the state. Red facet-grade and star almandite
garnet are produced from alluvial deposits at a number of locations.
Opals are produced at many locations, some yielding yellow or blue facet grade stones or fire opals.
Montana Gemstones
Montana's top gemstone product is
sapphires. Yogo Gulch sapphires have been famous for over 100 years and production continues. Sapphires are produced from both rock and alluvial deposits and in a wide range of colors which include: blues, blue-greens, greens, pinks, pale reds, purples, yellows and oranges. Much of the production is from dig-for-fee operations. Some gem-grade
garnets are produced from alluvial deposits which are mainly of industrial quality.
Arkansas Gemstones
Arkansas's most important gemstone material is
quartz. A very popular Arkansas gem is
rock crystal which is produced and sold as specimens and also for faceted stones, beads, carvings, spheres and decorative items. Exceptional specimens of rock crystal can sell for thousands of dollars. Faceted rock crystal is sold under the trade name of "Hot Springs Diamond" and clear, undamaged single crystals are made into pendants, earrings and other jewelry. In addition to rock crystal, Arkansas produces other quartz gems including agate, chert, jasper, opal, petrified wood and smoky quartz (frequently heat-treated rock crystal).
Nevada Gemstones
Nevada
opal from Virgin Valley is widely known for its intense color and large size stones. These deposits are replacements of woody materials and nodules found within clays. This opal is produced by a few small operations and dig-for-fee mines. Nevada has a long history of turquoise production but there is little recent activity.
