ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle, Metallic
Uneven, Conchoidal, UnevenArthur Thomas, Brittle
BeAlSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Fe2+ CO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references