Uneven, Uneven, Gemstones of the world (2001) More from other references
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
(Cs,K,Rb)Al 4Be 4(B,Be) 12O 28Anthony et al , Handbook of mineralogy (2001)