Gahnite and Blue John Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
4.00-4.62
  
3.00-3.25
  
Fracture
Conchoidal, Uneven
  
Not Available
  
Cleavage
Indistinct parting on [111]
  
Not Available
  
Mohs Hardness
7.5-8
  
Not Available
  
Chemical Composition
ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
  
CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Gahnite and Blue John Chemical Formula
While comparing Gahnite and Blue John 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 Gahnite and Blue John chemical formula.
- Chemical formula of Gahnite- ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
- Chemical formula of Blue John- CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)
Gahnite and Blue John Specific Gravity
Another important criteria for qualitative analysis of gemstones is Gahnite and Blue John Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Gahnite and Blue John Optical Properties during the identification of gemstone. Specific gravity of Gahnite is 3.00-3.25 whereas that of Blue John is 3.00-3.25.