Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Uneven, Gems, Sixth Edition (2006)
Ag 3AsS 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Al 2O 3Michael OâDonoghue , Gems, Sixth Edition (2006)