ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Al 2(PO 4)(OH) 3Michael OâDonoghue , Gems, Sixth Edition (2006)
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.