Biotite and Feldspar Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.7-3.3
  
2.56-2.75
  
Fracture
Uneven, Even, Yellow, White
  
Uneven, Conchoidal, Uneven, Conchoidal, Gemstones of the world (2001)
  
Cleavage
Perfect on the {001}
  
two or three
  
Mohs Hardness
2.5-3.0
  
6-6.5
  
Chemical Composition
K(Mg,Fe++)3[AlSi3O10(OH,F)2
  
Not Available
  
Biotite and Feldspar Chemical Formula
While comparing Biotite and Feldspar 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 Biotite and Feldspar chemical formula.
- Chemical formula of Biotite- K(Mg,Fe++)3[AlSi3O10(OH,F)2
>
Biotite and Feldspar Specific Gravity
Another important criteria for qualitative analysis of gemstones is Biotite and Feldspar Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Biotite and Feldspar Optical Properties during the identification of gemstone. Specific gravity of Biotite is 2.56-2.75 whereas that of Feldspar is 2.56-2.75.