Cassiterite, << kuh SIHT uh ryt, >> is the only important ore mineral of tin. It is sometimes called tinstone. Cassiterite usually has a slight metallic luster, with a brown or black color. Cassiterite usually occurs in veins associated with quartz, and it is found either in or near granite rocks. Countries that are major producers of cassiterite include Brazil, Bolivia, China, Indonesia, Malaysia, and Thailand. See also Tin .
