Australia
Afghanistan, Pakistan, Burma, Brazil, Madagascar, USA, Canada, Russia, Madagascar, Brazil, Canada, Mexico, Madagascar, Brazil, Canada, Mexico
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Gemstones of the world (2001), UnevenWalter Schumann, Gemstones of the world (2001)