Southern and central Africa
Mexico, Southern and central Africa
White, Colorless, Blue, Red, Green, Yellow, Violet
Brownish, Red, Yellow, White, Brown, orange
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
Pb 5(AsO 4) 3ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references