1 Physical Properties
1.1 Tenacity
Not Available
Not Available
1.4 Solubility
Not Available
Not Available
1.6 Durability
Not Available
Not Available
1.7 Specific Gravity
1.4 Fracture
Conchoidal, Conchoidal, Gemstones of the world (2001)
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009)
1.5 Cleavage
Not Available
Good in one direction
1.6 Mohs Hardness
1.13 Chemical Composition
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
(Fe,Mn)Ta 2O 6Walter Schumann , Gemstones of the world (2001) More from other references