Beryl (Molecule of the Month for March 1997)
Beryllium aluminum silicate. Relative amounts of additional metals give rise to the different color varieties.
Everyone admires the green fire of emerald and the watery blue charm of aquamarine, but not many realize that they are different colors of the same mineral: beryl. There are other members of the beryl family much less known then their famous cousins. Pink and peach morganite, named after gem collector extraodinaire J.P. Morgan; heliodor, also known as golden beryl; rare red beryl, which is as red as emerald is green; pale green beryl, which is a green version of aquamarine; and colorless beryl, or goshenite, which shows off the brilliance of this gem family.
In fact the word brilliance is probably derived from the ancient greek word for beryl, berullos, which means crystal.
Morganite is probably the most popular of the other beryls. It has a pastel pink to peach or lavender which is similar in intensity to the blue of aquamarine. It was first discovered in California in the Pala pegmatites. It was also discovered in 1908 in Madagascar. There are also deposits in Brazil, Mozambique, Namibia, Afghanistan, and Russia. However, morganite is relatively rare, which stands in the way of it becoming a jewelry stone. The largest faceted morganite is a 598.70-carat cushion-shape from Madagascar in the collection of the British Museum.
Heliodor, or golden beryl, is named after the greek words for sun helios and gift doron. The sunny yellow color of this beryl lives up to its name. Heliodor was discovered in Namibia in 1910 in a pegmatite that also produced aquamarine, which is also colored by iron. Heliodore is also found in Brazil and Madagascar. The largest faceted heliodor, 2,054 carats, is on display at the Smithsonian Institution in Washington D.C.
Red beryl is the rarest member of the beryl family. It is mined in only one place: the Wah Wah Mountains in Utah. The color is stoplight red. Unfortunately this deposit produces only a small quantity of this gem, and most of the gems produced are under a carat in size, and many have inclusions. Specimens that are over a carat and clean are fantastically rare and are priced as such.
Colorless beryl, which is also known as goshenite, is also relatively rare. It is named after a deposit where it was found in Goshen, Massachusetts. The Greeks used colorless beryl as lenses; the first spectacles were probably beryl.
All the gemstones in the beryl family are brilliant and durable and perfect for jewelry use.
Formal Chemical Name (IUPAC)
Update by Karl Harrison
(Molecule of the Month for March 1997 )