Emerald,
the green variety of beryl, of which aquamarine is the
blue variety. Chemically, it is a beryllium-aluminum
silicate whose color is due to small quantities of
chromium compounds. The emerald was highly esteemed in
antiquity; the stones were used for ornaments in early
Egypt where some of the first emeralds were mined. The
finest emeralds are found in South America in
Colombia, where they have been mined for over 400
years. The gem was a favorite in pre-Columbian Mexico
and Peru, where it was cut in intricate designs. The
treasure taken back to Spain by early explorers
included emeralds. Good emeralds are the most highly
valued of gem stones. India, Zimbabwe, and Australia
are minor sources of the natural stones. Synthetic
emeralds are also manufactured in Germany, France, and
the United States. The Oriental emerald, a different
gem, is the transparent green variety of corundum. |