Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{010} moderate, {100} imperfect
Fe 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)
(Mg,Fe2+ ) 5Al(Si 3Al)O 10(OH) 8Anthony et al , Handbook of mineralogy (2001)