Emerald is the green gemstone variety of the mineral Beryl (the blue variety of the mineral Beryl is Aquamarine). Beryl is beryllium aluminum silicate, with the known chemical composition of Be3Al2Si6O18.
Emerald crystals are hexagonal in nature. Large Emerald deposits are
currently mined in Colombia, Brazil, and Zambia. Emeralds are mined
throughout the world (Pakistan, Afghanistan, Russia, Australia, United
States) but these are the three major sources. The Zambian and
Brazilian Emeralds may be colored due to the presence of vanadium,
whereas Colombian Emeralds usually achieve their coloration from the
presence of chromium.
Emeralds have been treasured as adornments in the
form of jewelry for centuries. Emeralds are at least twenty times more
rare than diamonds, but in the finest grades sell for approximately the
same per-carat price as diamonds. Emeralds are readily available in
lesser grades and even very large sizes, but are exceedingly rare in
fine grades in any size.
Widely recognized as the Birthstone for May and
Astrological affiliation with Cancer (June 22 / July 22), Emerald is
also the celebrated gemstone of choice for 20th and 35th Wedding
Anniversary. The Emerald continues to be one of the most popular of
precious gemstones, rivaling Diamonds, Rubies and Sapphires.