Gems, Conchoidal, Brittle
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Ca 3Ti4+2(Fe3+2Si)O 12Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
KAlSi 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references