Staurolite and Gahnite Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.7-3.8
  
4.00-4.62
  
Fracture
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
  
Conchoidal, Uneven
  
Cleavage
Distinct on {010}
  
Indistinct parting on [111]
  
Mohs Hardness
7-7.5
  
7.5-8
  
Chemical Composition
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
  
ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
  
Staurolite and Gahnite Chemical Formula
While comparing Staurolite and Gahnite 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 Staurolite and Gahnite chemical formula.
- Chemical formula of Staurolite- (Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
- Chemical formula of Gahnite- ZnAl 2O 4Michael OâDonoghue , Gems, Sixth Edition (2006)
Staurolite and Gahnite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Staurolite and Gahnite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Staurolite and Gahnite Optical Properties during the identification of gemstone. Specific gravity of Staurolite is 4.00-4.62 whereas that of Gahnite is 4.00-4.62.