Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Subconchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
KCa 2AlBe 2Si 12O 30 · 0.5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Al2SiO4(F,OH)2