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, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
Conchoidal, Brittle, Conchoidal
1.6 Cleavage
None
{010} perfect, {110} distinct, {100} in traces
1.7 Mohs Hardness
1.8 Chemical Composition
NaFe3+3Fe3+6(BO 3) 3Si 6O 18(O,OH) 4Anthony et al , Handbook of Mineralogy (2001)
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references