White, Colorless, Blue, Red, Green, Yellow, Violet
White, Colorless, Blue, Red, Green, Yellow, Violet
ConchoidalArthur Thomas, Gemstones (2009)
Conchoidal, Gemstones of the world (2001)
(Ca,Mg,Mn)SiO 3Gemdat.org , Management Team (2012)
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)