ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Splintery, Conchoidal, Uneven, Splintery, Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001)
SiO 2 + H 2OUlrich Henn and Claudio C.
SiO 2Arthur Thomas , Gemstones (2009)