Achroite and Biotite Physical Properties
Tenacity
Not Available
  
Brittle
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
2.90-3.40
  
2.7-3.3
  
Fracture
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
  
Uneven, Even, Yellow, White
  
Cleavage
Not Available
  
Perfect on the {001}
  
Mohs Hardness
7-7.5
  
2.5-3.0
  
Chemical Composition
Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.
  
K(Mg,Fe++)3[AlSi3O10(OH,F)2
  
Achroite and Biotite Chemical Formula
While comparing Achroite and Biotite 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 Achroite and Biotite chemical formula.
- Chemical formula of Achroite- Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) Formula given for elbaite.
- Chemical formula of Biotite- K(Mg,Fe++)3[AlSi3O10(OH,F)2
Achroite and Biotite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Achroite and Biotite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Achroite and Biotite Optical Properties during the identification of gemstone. Specific gravity of Achroite is 2.7-3.3 whereas that of Biotite is 2.7-3.3.