1 Physical Properties
1.1 Tenacity
1.2 Solubility
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
2.54-2.783.90-4.05
1
7.18
1.5 Fracture
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, Gems, Difficult, Fibrous
1.6 Cleavage
Good in three directions
None – parting in 3 directions
1.7 Mohs Hardness
1.8 Chemical Composition
K(Ca,Na) 2Si 4O 10(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Al 2O 3Arthur Thomas , Gemstones (2009)