ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.
CaMoO 4Michael OâDonoghue , Gems, Sixth Edition (2006)