Corundum and Sapphire Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
insoluble
  
insoluble
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.90-4.05
  
3.95-4.03
  
Fracture
Uneven, Uneven, Gems, Difficult, Fibrous
  
Uneven, Uneven, Gems, Sixth Edition (2006)
  
Cleavage
None – parting in 3 directions
  
None, but may exhibit parting
  
Mohs Hardness
9
  
9
  
Chemical Composition
Al 2O 3Arthur Thomas , Gemstones (2009)
  
Al 2 O 3
  
Corundum and Sapphire Chemical Formula
While comparing Corundum and Sapphire 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 Corundum and Sapphire chemical formula.
- Chemical formula of Corundum- Al 2O 3Arthur Thomas , Gemstones (2009)
- Chemical formula of Sapphire- Al 2 O 3
Corundum and Sapphire Specific Gravity
Another important criteria for qualitative analysis of gemstones is Corundum and Sapphire Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Corundum and Sapphire Optical Properties during the identification of gemstone. Specific gravity of Corundum is 3.95-4.03 whereas that of Sapphire is 3.95-4.03.