Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Irregular, Irregular, Gemstones of the world (2001)
PbSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
CaCO 3Ulrich Henn and Claudio C.