Grandidierite and Alunite Physical Properties
Tenacity
Not Available
  
Brittle
  
Solubility
Not Available
  
Soluble
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.85-3.00
  
2.6-2.9
  
Fracture
Brittle, UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
  
Conchoidal, Uneven
  
Cleavage
Perfect
  
On {0001}, perfect
  
Mohs Hardness
7.5
  
3.5-4
  
Chemical Composition
(Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.
  
KAl3(SO4)2(OH)6
  
Grandidierite and Alunite Chemical Formula
While comparing Grandidierite and Alunite 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 Grandidierite and Alunite chemical formula.
- Chemical formula of Grandidierite- (Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.
- Chemical formula of Alunite- KAl3(SO4)2(OH)6
Grandidierite and Alunite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Grandidierite and Alunite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Grandidierite and Alunite Optical Properties during the identification of gemstone. Specific gravity of Grandidierite is 2.6-2.9 whereas that of Alunite is 2.6-2.9.