Brittle, UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
(Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references