Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), (e.g. graphite).
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.
Pb 2(CO 3)Cl 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references