Afghanistan, Pakistan, Burma, Brazil, Madagascar, USA, Canada, Russia, Madagascar, Brazil, Canada, Mexico, Madagascar, Brazil, Canada, Mexico
Australia, Canada, Guatemala, Italy, Kenya, Mexico, Turkey, Mexico, Guatemala, Mexico, Guatemala
Gemstones of the world (2001), UnevenWalter Schumann, Gemstones of the world (2001)
Conchoidal, ConchoidalWalter Schumann, Conchoidal