Kyanite and Foitite Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.53-3.65
  
3.17
  
Fracture
Splintery, Brittle, Metallic
  
Handbook of mineralogy (2001)
  
Cleavage
[100] perfect [010] imperfect with 79° angle between
  
None
  
Mohs Hardness
4-7
  
7
  
Chemical Composition
Not Available
  
Na x[Fe2+2(Al,Fe3+ )]Al 6(BO 3) 3Si 6O 18(OH) 4Anthony et al , Handbook of mineralogy (2001)
  
Kyanite and Foitite Chemical Formula
While comparing Kyanite and Foitite 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 Foitite chemical formula.
>- Chemical formula of Foitite- Na x[Fe2+2(Al,Fe3+ )]Al 6(BO 3) 3Si 6O 18(OH) 4Anthony et al , Handbook of mineralogy (2001)
Kyanite and Foitite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Kyanite and Foitite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Kyanite and Foitite Optical Properties during the identification of gemstone. Specific gravity of Kyanite is 3.17 whereas that of Foitite is 3.17.