Cordierite and Common Opal Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.57-2.66
  
1.98-2.50
  
Fracture
Subconchoidal, Conchoidal, Brittle
  
Conchoidal, Conchoidal, Gemstones of the world (2001)
  
Cleavage
Fair on {100}, poor on {001} and {010}
  
Not Available
  
Mohs Hardness
7-7.5
  
5.5-6.5
  
Chemical Composition
Mg2Al4Si5O18
  
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
  
Cordierite and Common Opal Chemical Formula
While comparing Cordierite and Common Opal 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 Common Opal chemical formula.
- Chemical formula of Cordierite- Mg2Al4Si5O18
- Chemical formula of Common Opal- SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
Cordierite and Common Opal Specific Gravity
Another important criteria for qualitative analysis of gemstones is Cordierite and Common Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Cordierite and Common Opal Optical Properties during the identification of gemstone. Specific gravity of Cordierite is 1.98-2.50 whereas that of Common Opal is 1.98-2.50.