If you were born in May, your birthstone is the emerald, a type of beryl colored green by chromium. Perfect emeralds are among the rarest of gemstones.
The emerald belongs to the beryl family of minerals that include aquamarine (one of March’s birthstones), heliodor, and morganite. Beryl, or beryllium aluminum silicate in chemical jargon, is a six-sided symmetrical crystal. Beryl contains beryllium, aluminum, silicon, and oxygen.
Emeralds vary in color from light to deep green. It’s commonly thought that an emerald’s color derives from the presence of chromium and/or vanadium replacing some of the aluminum in the mineral’s structure. The stone can, however, lose its color when heated strongly.
Several famous historical artifacts were made of emeralds. Among them is the Crown of the Andes, said to be made from emeralds worn by Atahualpa, the last Inca (king) of Peru. The crown is set with about 450 emeralds, collectively weighing…
View original post 387 more words