Uneven, Conchoidal, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Mg 3(SiO 4)(F,OH) 2Anthony et al , Handbook of Mineralogy (2001)