Colorless, White, gray, Brownish, Greenish
White, Colorless, Blue, Red, Green, Yellow, Violet
KAl 2AlSi 3O 10(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)