Topaz is a fluorosilicate and can contain trace elements that cause different colours within the gemstone. Its name originates from the Greek word "topazion", a Red Sea Island often covered in mist. In the Middle Ages the name topaz was used to refer to any yellow gemstone. Deposits of topaz are found in Russia, Siberia, Brazil, Sri Lanka, Africa and China, Japan, Pakistan, Myanmar, Nigeria, Australia, Mexico, and in the United States.

Source: Encyclopedia of gemstones and minerals.