Not Available, Southern and central Africa
Afghanistan, Pakistan, Burma, Brazil, Madagascar, USA, Canada, Russia, Madagascar, Brazil, Canada, Mexico, Madagascar, Brazil, Canada, Mexico
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
Gemstones of the world (2001), UnevenWalter Schumann, Gemstones of the world (2001)