Gems, Uneven
Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
KAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references