Emerald is green beryl, colored by trace amounts of chromium and sometimes vanadium.
Emeralds in antiquity were mined by the Egyptians and in Austria, as well as Swat in northern Pakistan.Colombian emeralds are generally the most prized due to their transparency and fire. Some of the rarest emeralds come from the two main emerald belts in the Eastern Ranges of the Colombian Andes: Muzo and Coscuez west of the Altiplano Cundiboyacense, and Chivor and Somondoco to the east. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. In 1998, emeralds were discovered in the Yukon, Canada. (Wikipedia)