Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
PbCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references