ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
SiO 2Ulrich Henn and Claudio C.
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references