Emerald is a variety of the mineral called beryl, which next to it contains chromium and vanadium, which gives plants their green color and a hardness of 7.5 to 8 on the Mohs scale. This mineral is a cyclosilicate, and its specific weight is between 2.65 and 2.90. It is a silicate of beryllium and aluminum chromium chemical formula Be3Al2 (SiO3) 6.
It is a very valued gemstone because of its rarity, since from antiquity precious stones like malachite green were discovered, but the only emerald crystal. Your name, possibly Persian, meaning green stone and its tone has given name to the emerald green.
It is found in large quantities in the department of Boyaca in Colombia (Muzo, Chivor, Otanche and Coscuez), and Brazil, also to a lesser extent in Zambia, where the deposits are less bulky. The largest producer of emeralds in the world is Colombia followed by Brazil.
In the Eastern Desert of Egypt, not far from the Red Sea, there are mines that were exploited possibly 3,500 years ago. Many years after the discovery of emeralds, Cleopatra came to own the mines, because I felt a special fascination for these stones.
In the other hemisphere, many mines large amounts of aquamarine Brazil, another gemstone (but less commercial value of the emerald) whose name comes from the resemblance of its color to the sea are drawn. Despite their differences in price, emerald and aquamarine have much in common: they are made of the same mineral. The difference in color is caused by impurities that give each its characteristic color.
Both the emerald and aquamarine are formed by a mineral beryl, which is colorless when it is pure. It is a small amount of chromium that gives emerald its intense green color, while iron is responsible for giving her light blue shades to aquamarine. However, colorless beryl may also be "dressed" with other colors depending on their electrical charge, manganese impurities in beryl gems can produce pink or red, as morganite. And the presence of iron in the beryl aquamarine not only produces, but sometimes a type of beryl colored with a deep yellow, as the heliodoro is obtained.
Special mention emerald mill, located in some mines of Colombia, for his strange star-shaped due to crystal growth in various directions.