Blue John and Feldspar Physical Properties
Tenacity
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Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.00-3.25
  
2.56-2.75
  
Fracture
Not Available
  
Uneven, Conchoidal, Uneven, Conchoidal, Gemstones of the world (2001)
  
Cleavage
Not Available
  
two or three
  
Mohs Hardness
Not Available
  
6-6.5
  
Chemical Composition
CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Not Available
  
Blue John and Feldspar Chemical Formula
While comparing Blue John and Feldspar 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 Blue John and Feldspar chemical formula.
- Chemical formula of Blue John- CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)
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Blue John and Feldspar Specific Gravity
Another important criteria for qualitative analysis of gemstones is Blue John and Feldspar Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Blue John and Feldspar Optical Properties during the identification of gemstone. Specific gravity of Blue John is 2.56-2.75 whereas that of Feldspar is 2.56-2.75.