Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle
CaBSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references