UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Subconchoidal, Uneven, Conchoidal, Uneven
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.
Mn2+ Al(PO 4)(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)