Australia, Spain, Brazil, Germany, Australia, Spain, Brazil, Germany, Australia, Spain, Brazil
Afghanistan, Brazil, Southern and central Africa, Madagascar, Russia, USA, Zimbabwe
Conchoidal, Splintery, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)