Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Gems, Sixth Edition (2006), Gems, Sixth Edition (2006)
Fe 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)
SiO 2Michael OâDonoghue , Gems, Sixth Edition (2006)