The beryl species is one of the most important in the gemstone world. Two varieties of beryl -- the deep green emerald, and the blue aquamarine -- are among the most famous of all gem varieties. All of the other colors of beryl are known as precious beryl.
Precious beryl occurs in yellow, green, golden, pink, red and colorless. All of the beryls are aluminum beryllium silicate by chemical composition. Beryl is highly regarded for its very good hardness -- 7.5 to 8 on the Mohs scale -- and its lack of cleavage. It does not have a notably high refractive index, with a rating of 1.562 to 1.602, between quartz and topaz. But many of the beryls have excellent clarity and transparency, so they make very attractive gemstones. Interestingly, the most valuable beryl -- emerald -- tends to be the least transparent and most included. However, it makes up for those shortcomings with a color that is unique in the gemstone world.
The colorless precious beryl is known as goshenite. It is named after the very small town of Goshen in western Massachusetts where it was first described. Goshenite is found in relatively many beryl deposits around the world, so it is perhaps the most common and least expensive form of beryl.
Goshenite was once used for manufacturing eyeglasses and lenses owing to its excellent transparency. These days, it is most commonly used as a gemstone and is also considered a source of beryllium. Before the introduction of diamond simulants such as cubic zirconium, goshenite was often used a diamond replacement. The brilliance and fire could be improved by placing silver foil behind the cut stone.
Since goshenite is relatively plentiful, usually only very clean and transparent specimens are cut as gemstones. Goshenite competes in the market with other colorless gems such as white sapphire, white zircon and white topaz.
Goshenite deposits are found in Brazil, China, Burma, Canada, Mexico, Namibia, Pakistan, Russia and the United States. In the US, goshenite is found not only in Massachusetts, but also in California, Colorado, Connecticut, Idaho, Maine, New Hampshire and North and South Dakota.