Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.60-2.642.90-3.10
1
7.18
👆🏻
Fracture
Uneven, Splintery, Conchoidal
Uneven, Conchoidal
Cleavage
Absent
Poor/indistinct on {1120} and {1011}
Mohs Hardness
6.5-77
2
10
👆🏻
Chemical Composition
SiO 2Arthur Thomas , Gemstones (2009)
Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) More from other references