Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium.Beryl has a hardness of 7.5 – 8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor. The word “emerald” comes from Latin smaragdus, via Greek smaragdos, its original source being a Semitic word or the Sanskrit word, marakata, meaning “emerald” or “green”.
Emeralds in antiquity were mined by the Egyptians and in Austria, as well as Swat in northern Pakistan.
A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia. A trapiche emerald exhibits a “star” pattern; it has raylike spokes of dark carbon impurities that give the emerald a six-pointed radial pattern. It is named for the trapiche, a grinding wheel used to process sugarcane in the region. Colombian emeralds are generally the most prized due to their transparency and fire. Some of the most rare emeralds come from three main emerald mining areas in Colombia: Muzo, Coscuez, and Chivor. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. In the US, emeralds can be found in Gastonia, North Carolina. In 1998, emeralds were discovered in the Yukon Territory, Canada.