Uneven, Subconchoidal, UnevenArthur Thomas, Fibrous
Uneven, Conchoidal, Brittle, Metallic, ConchoidalArthur Thomas, Gemstones (2009)
Al 3(PO 4) 2(OH,F) 3 · 5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 3Cr 2(SiO 4) 3Ulrich Henn and Claudio C.