1 Physical Properties
1.1 Tenacity
Not Available
Not Available
1.2 Solubility
Not Available
Not Available
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009)
Gems, Sixth Edition (2006), Gems, Sixth Edition (2006), Uneven
1.6 Cleavage
Good in one direction
From the Greek, oligos and kasein, little cleavage.
1.7 Mohs Hardness
1.8 Chemical Composition
(Fe,Mn)Ta 2O 6Walter Schumann , Gemstones of the world (2001) More from other references
Na(90-70%)Ca(10-30%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)