Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
KAlSi 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
CaBSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references