The most important Emerald deposits are located in Colombia. The Muzo mine, already exploited since the time of the Incas, was forgotten, but then it was rediscovered in the 17th century. Another important deposit is the Chivor mine. The latter was also used by the Incas, and then by the Spaniards who operated it very hard. This one was also forgotten, to be reopened again at the beginning of this century. It should be noted that there are several deposits of Emeralds in Brazil in Bahia, Goiás and Minas Gerais. Other mines are located in Zimbabwe (Sandawana), in Trasvaal, Urals, Zambia, Pakistan, and in Afghanistan. Some beautifully coloured Emeralds present numerous inclusions. It was discovered a long time that by soaking them in oil, some of these inclusions become less visible and the transparency of the stone improves. Nowadays, materials such as polymers or dyes are used, which must be specifically indicated, because the quality and value of these Emerald is thus reduced.
