1 Physical Properties
1.1 Tenacity
1.2 Solubility
Not Available
Not Available
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Conchoidal, Uneven, Brittle
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009)
1.6 Cleavage
Imperfect on {001}, indistinct on {011}
Good on {100}
1.7 Mohs Hardness
1.8 Chemical Composition
Not Available
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references