Uneven, ConchoidalArthur Thomas, Brittle, Metallic
Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
Pb 5(PO 4) 3ClArthur Thomas , Gemstones (2009)
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references