Gems, Sixth Edition (2006), Gems, Sixth Edition (2006), Uneven
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
From the Greek, oligos and kasein, little cleavage.
Perfect on [10 1 1] three directions with angle of 74° 55
Na(90-70%)Ca(10-30%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
CaCO 3Ulrich Henn and Claudio C.