Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Uneven, Subconchoidal, Splintery
Good on {110}, poor on {100}
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
Poor on {110} and {100} very poor on {001}
Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4