Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
(Be,Cs) 3Al 2Si 6O 18 · 0.5H 2OUlrich Henn and Claudio C.
Pb 5(AsO 4) 3ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references