1 Physical Properties
1.1 Tenacity
Not Available
Very brittle
1.2 Solubility
1.3 Durability
1.4 Specific Gravity
1.5 Fracture
Uneven, Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001)
Conchoidal, Brittle, Conchoidal
1.6 Cleavage
Perfect {010}, imperfect {100}
{010} perfect, {110} distinct, {100} in traces
1.7 Mohs Hardness
1.8 Chemical Composition
Ca2Al3(SiO4)3(OH)
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references