Uneven, Sub-Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
ZnCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Fe 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)