Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
2.50-3.002.50-2.80
1
7.18
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Fracture
Uneven-Conchoidal, ConchoidalWalter Schumann
-
Cleavage
3,6
Perfect
Mohs Hardness
5.55-6.5
2
10
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Chemical Composition
The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)8Al6Si6O24(S,SO)4
Na 4(Al,Si) 12O 24Cl to Ca 4(Si,Al) 12O 24(CO 3,SO 4)Arthur Thomas , Gemstones (2009)