Hercynite and Blue John Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
4.39
  
3.00-3.25
  
Fracture
ConchoidalGemdat.org, Uneven
  
Not Available
  
Cleavage
{111} Indistinct, {111} Indistinct, {111} Indistinct
  
Not Available
  
Mohs Hardness
7.5-8
  
Not Available
  
Chemical Composition
Fe2+ Al 2O 4Gemdat.org , Management Team (2012)
  
CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Hercynite and Blue John Chemical Formula
While comparing Hercynite 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 Hercynite and Blue John chemical formula.
- Chemical formula of Hercynite- Fe2+ Al 2O 4Gemdat.org , Management Team (2012)
- Chemical formula of Blue John- CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006)
Hercynite and Blue John Specific Gravity
Another important criteria for qualitative analysis of gemstones is Hercynite and Blue John Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Hercynite and Blue John Optical Properties during the identification of gemstone. Specific gravity of Hercynite is 3.00-3.25 whereas that of Blue John is 3.00-3.25.