Alunite and Star Sapphire Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Soluble
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.6-2.9
  
3.90-4.05
  
Fracture
Conchoidal, Uneven
  
Not Available
  
Cleavage
On {0001}, perfect
  
Not Available
  
Mohs Hardness
3.5-4
  
Not Available
  
Chemical Composition
KAl3(SO4)2(OH)6
  
Al 2O 3Ulrich Henn and Claudio C.
  
Alunite and Star Sapphire Chemical Formula
While comparing Alunite and Star 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 Alunite and Star Sapphire chemical formula.
- Chemical formula of Alunite- KAl3(SO4)2(OH)6
- Chemical formula of Star Sapphire- Al 2O 3Ulrich Henn and Claudio C.
Alunite and Star Sapphire Specific Gravity
Another important criteria for qualitative analysis of gemstones is Alunite and Star Sapphire Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Alunite and Star Sapphire Optical Properties during the identification of gemstone. Specific gravity of Alunite is 3.90-4.05 whereas that of Star Sapphire is 3.90-4.05.