Cordierite and Gahnite Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.57-2.66
  
4.00-4.62
  
Fracture
Subconchoidal, Conchoidal, Brittle
  
Conchoidal, Uneven
  
Cleavage
Fair on {100}, poor on {001} and {010}
  
Indistinct parting on [111]
  
Mohs Hardness
7-7.5
  
7.5-8
  
Chemical Composition
Mg2Al4Si5O18
  
ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Cordierite and Gahnite Chemical Formula
While comparing Cordierite and Gahnite 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 Cordierite and Gahnite chemical formula.
- Chemical formula of Cordierite- Mg2Al4Si5O18
- Chemical formula of Gahnite- ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
Cordierite and Gahnite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Cordierite and Gahnite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Cordierite and Gahnite Optical Properties during the identification of gemstone. Specific gravity of Cordierite is 4.00-4.62 whereas that of Gahnite is 4.00-4.62.