ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Conchoidal to uneven, Brittle, Metallic, Uneven, ConchoidalWalter Schumann, Brittle, Metallic
{100} perfect; {110} and {1 1 0} good; {010} poor
Distinct on {110}, imperfect on {010}, poor on {001}
(Ca,Mn2+ )Si 3O 9Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
BeAl 2 O 4