Afghanistan, Brazil, Southern and central Africa, Madagascar, Russia, USA, Zimbabwe
Australia, Canada, Guatemala, Italy, Kenya, Mexico, Turkey, Mexico, Guatemala, Mexico, Guatemala
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Conchoidal, ConchoidalWalter Schumann, Conchoidal