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
Not Available
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
1.6 Cleavage
Not Available
Perfect on {001}, good on {210}, poor on {010}
1.7 Mohs Hardness
1.8 Chemical Composition
NaFe 3+ 3 Al 6 (BO 3 ) 3 Si 6 O 18 (O,F,OH) 4 Anthony et al, Handbook of mineralogy (2001)
SrSO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references