Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
111 (perfect in four directions)
{0001} Imperfect, {1120} Imperfect
C
KCa 2AlBe 2Si 12O 30 · 0.5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references