Some people reserve the name for a blue, unbanded, translucent material.Ĭharoite is a light lavender to deep purple silicate mineral that has swirling, fibrous, or spotted patterns. Not recommended if the stone will be in direct contact with your skin.Ĭhalcedony is a name used for any cryptocrystalline quartz such as agate, jasper, petrified wood, chrysoprase, bloodstone, onyx, sard, and carnelian. Some specimens reportedly contain arsenic. Often called Bumblebee "Agate" or "Jasper," it is instead a rock formed at several volcanic vents in Indonesia. It is sometimes cut and polished as a gemstone. "Boulder opal" is a name used for a rough or cut rock material that displays precious opal within its surrounding rock matrix.Ī bronze to greenish variety of enstatite with a metallic luster. It has been a popular gem for thousands of years. These red splashes remind people of blood, and that is how the stone received its name. This specimen here has blue play-of-color on a black base.īloodstone is a dark green variety of jasper that displays numerous splashes of red color. The name "black opal" is used for an opal with a black base color. "Benitoite" is a rare barium titanium silicate mineral found at a few locations worldwide but in gem quality at only in one location in San Benito County, California. "Beryl" is a mineral with several gem varieties based upon color. It is cut into cabochons for use in jewelry that will not encounter wear. Best used as cabochons in jewelry that will not encounter wear.Ī beautiful blue and green gem material that is a combination of the copper minerals, azurite and malachite. Associated with malachite and chrysocolla soft (H: 3.5-4) cleaves easily. Light enters the stone, reflects from the grains and produces a flash known as aventurescence.Ī beautiful dark blue opaque gem material found near copper deposits. The richer color is much more desired.Īventurine is a quartz variety that contains a blizzard of tiny reflective inclusions such as muscovite, hematite, or fuchsite. It ranges from a very light blue to a richly saturated blue. It receives its name from its seawater color. It is a "collector's gem" rather than a jewelry gem.Īquamarine is a blue variety of the mineral beryl.
It has a hardness of 5 on the Mohs scale and is brittle. These red chrome pyrope garnets are often found on ant hills in parts of the southwestern USA.Īpatite is a mineral that is cut as a gem when found in clear crystals with attractive colors.
A variety known as chiastolite has grains of graphite concentrated into a cross-shaped feature.Īnt hill garnet is a novelty gem that ants excavate, haul to the surface and deposit on their ant hill. Their fossilized shells are often cut and used as organic gems.Īndalusite is a metamorphic mineral that is strongly pleochroic and an underappreciated gem. All of the world's production of this organic gem is from a small area in Alberta, Canada.Īn extinct group of marine invertebrate animals that produced a chambered shell. It produces a bright flash of color that rivals opal and labradorite. It is commercially produced at only one mine in the world, located in eastern Bolivia.Īmmolite is a trade name used for iridescent ammonite shell. The color combination is caused by twinning. It is found in many locations around the world.Īmetrine is a bicolor quartz that is half AMEthyst and half ciTRINE. It is one of the most popular faceted gemstones and is sometimes cut en cabochon. It is an organic gem easily cut and polished into bright, lightweight gems.Īmethyst is a transparent variety of quartz that ranges from light lilac to deep purple in color. It usually has a yellowish to orangish brown color but can be white, greenish, bluish, or black. It has a Mohs hardness of 6 with perfect cleavage, so it is best used where it will not suffer abrasion or impact.Īmber is a fossil resin secreted by ancient trees. For that reason, it is common in jewelry.Īmazonite is a trade name given to a light green to bright green variety of microcline feldspar. It is a popular gem cut into cabochons, beads, and ornamental objects.Īlmandine garnet, also known as "almandite," is an iron-rich, red-to-purple garnet that is geologically very common and typically sells on the more affordable side of the garnet price range. It sometimes has a fibrous texture that produces a strong cat's-eye.Īgate is a cryptocrystalline quartz that is translucent and patterned with bands, plumes, dendrites, or inclusions that produce a colorful, interesting appearance. Actinolite is green to grayish green mineral of the amphibole group found in metamorphic rocks.
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