Splintery, Granular, Splintery, Granular, Gemstones (2009)
Gems, Conchoidal, Brittle
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
Ca 3Ti4+2(Fe3+2Si)O 12Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references