Ethiopia, Mexico, Honduras, Guatemala, Brazil, USA, Canada, Madagascar, Tanzania, Czech, Slovakia
Afghanistan, Brazil, Madagascar, Mozambique, Southern and central Africa, Russia, Sri Lanka
Black, Red
White, Colorless, Blue, Red, Green, Yellow, Violet
Not Available
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)