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