Southern and central Africa
Afghanistan, Pakistan, Burma, Brazil, Madagascar, USA, Canada, Russia, Madagascar, Brazil, Canada, Mexico, Madagascar, Brazil, Canada, Mexico
Handbook of mineralogy (2001)
Gemstones of the world (2001), UnevenWalter Schumann, Gemstones of the world (2001)
Weak: colorless light gray bluish grayAnthony et al
Strong trichroism: colorless pink violetHerve Nicolas Lazzarelli