Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Uneven, Sub-Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.
ZnCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references