Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.
Mg 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references