Coloured scanning electron micrograph (SEM) of fractured emerald. Emerald is a gemstone and a variety of the mineral beryl colored green by trace amounts of chromium and sometimes vanadium. Colombia is by far the world's largest producer of emeralds but emeralds are found all over the world. Emeralds have been held in high esteem since ancient times. For that reason, some of the most famous emeralds are to be seen in museums and collections. Magnification: x9000 when printed 10 centimetres wide.