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abalone
Abalone is a mollusk with a pearly shell that is often used in jewelry.
adamantine
Adamantine means having a diamond-like luster and hardness. It is derived from the Greek word adamas, meaning invincible, from which the name diamond is derived.
adularescence
Adularescence is the billowing shimmer of light floating across the surface of a moonstone. Only moonstones exhibit adularescence.
agate
Agate is a quartz crystal and a sub-variety of chalcedony. It is found in a wide range of pale colors including green, yellow, red, reddish-brown, white, and bluish white. On Mohs' scale of hardness, agate is 6.5 to 7. It has a waxy or dull luster, and primary agate sources include South of Brazil (Rio Grande do Sul), north of Uruguay, Australia (Queensland), China, India, the Caucasus, Madagascar, Mexico, Mongolia, Namibia, Wyoming, and Montana.
alexandrite
Alexandrite is a highly prized variety of chrysoberyl. In daylight, alexandrite appears green, and in tungsten light, it appears raspberry red. On Mohs' scale of hardness, alexandrite is 8.5. It has a strong vitreous luster, and primary alexandrite sources include Sri Lanka, Zimbabwe, and Brazil (Minas Gerais). Read on to learn more about <a href="/gemstones-101/alexandrite.aspx?">alexandrite</a>.
alloy
An alloy is a compound made up of two or more metals.
almandite/almandine
Almandite is a variety of garnet. It is usually found in a violet red hue. On Mohs' scale of hardness, almandite is 7.5. It has a vitreous luster, and primary sources for almandite garnet include Brazil, India, Madagascar, Sri Lanka, and the United States. Read on to learn more about garnet.
amber
Amber is a fossilized, organic mixture of pine resins, acids, and volatile oils dating back at least 30 million years. It comes from pine tree sap and is predominantly found in yellows and browns. On Mohs' scale of hardness, amber is only 2 to 2.5, so it is frequently treated with hardeners to make it durable enough for wear in jewelry. Amber has a vitreous luster but a resinous luster when polished. Primary amber sources include Russia (Kaliningrad), Sicily/Italy (called simetite), Rumania (called rumanite), Burma (Myanmar, called burmite), China, the Dominican Republic, Japan, Canada, Mexico, and the United States (Alaska and New Jersey).
amethyst
Amethyst is the most highly valued gemstone in the quartz family. It is found in a range of hues from blue-violet to pale reddish-violet. On Mohs' scale of hardness, amethyst is a respectable 7. Primary amethyst sources include Brazil (Rio Granda, Para), Madagascar, Zambia, Uruguay, Burma (Myanmar), India, Canada, Mexico, Namibia, Russia, Sri Lanka, and the United States (Arizona). Read on to learn more about amethyst.
ametrine
Ametrine is a quartz crystal that contains both amethyst and citrine. It is a bi-color gemstone that displays the violets of amethyst and the yellows of citrine. On Mohs' scale of hardness, ametrine ranks 7, just like amethyst and citrine. The only commercial source of ametrine in the world is the Anahi mine in Bolivia. Read on to learn more about ametrine.
amorphous
Amorphous is an adjective meaning shapeless or lacking crystal structure. Amber is an example of an amorphous gem.
andalusite
Andalusite is a naturally occurring pleochroic gemstone. As the stone is rotated, different colors and different intensities of colors can appear in andalusite, including olive green, rich reddish browns, and grayish green. Andalusite is so highly pleochroic that sometimes more than one color can be seen in it at once, without even having to turn the stone. On Mohs' scale of hardness, andalusite ranks 7 to 7.5. It has a vitreous or matte luster, and primary andalusite sources include Australia, Brazil, Canada, Russia, Spain (Andalusia, for which andalusite was named), Sri Lanka, and the United States.
andradite
Andradite is a gem species in the garnet family. The andradite species includes several significant gem varieties, most notably demantoid garnet but also melanite and topazolite. On Mohs' scale of hardness, andradite garnets range from 3.7 to 4.1.
anklet
An anklet is a short chain much like a bracelet, but anklets are slightly longer and are designed to be worn around the ankle.
apatite
Apatite is a naturally occurring beautiful gemstone. While it is known for its green and blue hues, apatite is also found in a wide variety of colors ranging from colorless to pink, yellow, and violet. On Mohs' scale of hardness, apatite is a relatively soft 5, so it's best suited for jewelry like earrings and pendants rather than rings or bracelets that are worn daily. Apatite has a vitreous luster, and primary apatite sources include Burma (Myanmar), Brazil, India, Kenya, Madagascar, Mexico, Norway, Sri Lanka, South Africa, and the United States. Read on to learn more about apatite.
aquamarine
Aquamarine is a member of the beryl family. It is known for its clear sky-blue color, but it is also found in a range of darker blues and greenish blues. On Mohs' scale of hardness, aquamarine is 7.5 to 8. Primary aquamarine sources include Brazil, Russia (the Ural Mountains), Australia (Queensland), Burma (Myanmar), China, India, Kenya, Madagascar, Mozambique, Namibia, Nigeria, Zambia, Zimbabwe, and the United States (Colorado). Read on to learn more about aquamarine.
Art Deco
The Art Deco style features linear, geometric patterns, abstract designs, and vibrant colors. Art Deco flourished in the 1920s and 1930s, synthesizing a variety of influences such as ancient Egyptian and Mediterranean culture with modern technology.
Art Nouveau
Art Nouveau is a decorative style (circa 1890-1914) noted for its free-flowing lines and natural motifs.
asterism
Asterism is the gemological term for the four- or six-rayed stars caused by light reflecting from needlelike inclusions within some gems. Asterism is visible when the stones are cut en cabochon.
average weight
We list the average carat weight for some of our gemstones and jewelry. These averages are calculated by adding all grades or measurements that comprise the inventory with regard to similar items or in a lot, and determining the closest weight.
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