Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
PbCu(SO 4)(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
CaBSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references