Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
SiCArthur Thomas , Gemstones (2009)