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