Kyanite and Lazurite Physical Properties
Tenacity
Brittle
  
Brittle
  
Solubility
Not Available
  
Soluble
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.53-3.65
  
2.75
  
Fracture
Splintery, Brittle, Metallic
  
Uneven, UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
  
Cleavage
[100] perfect [010] imperfect with 79° angle between
  
Imperfect on {110}
  
Mohs Hardness
4-7
  
5.5
  
Chemical Composition
Not Available
  
(Na,Ca) 8Al 6Si 6O 24(SO 4,S,Cl) 2Ulrich Henn and Claudio C.
  
Kyanite and Lazurite Chemical Formula
While comparing Kyanite and Lazurite physical properties, the important data you should know is its chemical composition. Since chemical formula defines the molecular structure of the crystal, most of the physical properties like color, tenacity, solubility are governed by Kyanite and Lazurite chemical formula.
>- Chemical formula of Lazurite- (Na,Ca) 8Al 6Si 6O 24(SO 4,S,Cl) 2Ulrich Henn and Claudio C.
Kyanite and Lazurite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Kyanite and Lazurite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Kyanite and Lazurite Optical Properties during the identification of gemstone. Specific gravity of Kyanite is 2.75 whereas that of Lazurite is 2.75.