ALEXANDRITE. The East African country of Tanzania is abundant with gemstone wealth. First known by Westerners for its diamonds, Tanzania emerged in the 1960s as a producer of a great variety of other gems such as tanzanite, ruby, garnet and alexandrite. Lake Manyara in the north and Tunduru in the south are two of the main mining areas of alexandrite in Tanzania. Best known for its emeralds, the deposit in Mayowa Village at the southern tip of Lake Manyara has regularly produced high quality ale