ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
(Cs,K,Rb)Al 4Be 4(B,Be) 12O 28Anthony et al , Handbook of mineralogy (2001)
KAlSi 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references