Gems, Conchoidal, Brittle
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Ca 3Ti4+2(Fe3+2Si)O 12Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
KNa 2Li(Fe2+ ,Mn2+ ) 2Ti 2Si 8O 24Michael OâDonoghue , Gems, Sixth Edition (2006)