Tenacity
-
Very brittle
Solubility
-
insoluble
Durability
-
-
Specific Gravity
2.50-2.803.30-3.40
1
7.18
👆🏻
Fracture
-
Conchoidal
Cleavage
Perfect
{010} perfect, {110} distinct, {100} in traces
Mohs Hardness
5-6.56.5-7
2
10
👆🏻
Chemical Composition
Na 4(Al,Si) 12O 24Cl to Ca 4(Si,Al) 12O 24(CO 3,SO 4)Arthur Thomas , Gemstones (2009)
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references