Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Uneven, UnevenArthur Thomas, Gemstones (2009)
CaCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Mg 3Si 4O 10(OH) 2Ulrich Henn and Claudio C.