Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
SiCArthur Thomas , Gemstones (2009)