1 Physical Properties
1.1 Tenacity
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)
Subconchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Irregular
1.6 Cleavage
None
{100} imperfect, {110} indistinct; partings on {111} or {011}
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)
SnO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references