Uneven, Sub-Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Handbook of mineralogy (2001)
ZnCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Ca,Mn2+ ) 2(SiO 3OH)(OH)Anthony et al , Handbook of Mineralogy (2001)