Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Metallic
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
PbCa 3Zn 4(SiO 4) 4Anthony et al , Handbook of mineralogy (2001)
BaSO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references