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