Cassiterite is a tin oxide mineral with a hardness of 6 to 7. Its name is derived from the Greek word for tin. It has a tetragonal crystal system and can be found in short, prismatic crystals, though it is more commonly found in massive, granular, radiated, fibrous, or botryoidal forms. It has an adamantine to metallic luster and its color ranges from reddish brown to brownish black, with occasional colorless specimens. While cassiterite can be cut into gems, high-quality pieces are rare. It has been discovered in Australia, Bolivia, Mexico, Malaysia, England, and Namibia.
