1 Physical Properties
1.1 Tenacity
Not Available
Very brittle
1.2 Solubility
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Uneven, Brittle, Metallic
Conchoidal, Brittle, Conchoidal
1.6 Cleavage
Perfect on [001] imperfect on [100]
{010} perfect, {110} distinct, {100} in traces
1.7 Mohs Hardness
1.8 Chemical Composition
(K,Na) 3(Fe2+ ,Mn) 7Ti 2Si 8O 24(O,OH) 7Anthony et al , Handbook of mineralogy (2001)
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references