Calcite is not commonly an important gem mineral because it is relatively fragile and soft (3 on the Moh’s scale of hardness). It is typically colorless or white, however due to impurities it can occur in shades of red, yellow, green, blue, violet, brown, and black. This 8.48ct lively reddish-orange calcite from Tanzania is rare and a wonderful addition to the National Gem Collection.
