White, Colorless, Blue, Red, Green, Yellow, Violet
Green, Yellow, Colorless, Grey, Brown, White, Red
Conchoidal, Conchoidal, Gemstones of the world (2001)
Uneven, ConchoidalArthur Thomas, Brittle, Metallic
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)