Staurolite and Opal Physical Properties
Tenacity
Brittle
  
BrittleWalter Schumann
  
Solubility
Not Available
  
hot salt water
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.7-3.8
  
1.98-2.25
  
Fracture
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
  
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Brittle
  
Cleavage
Distinct on {010}
  
None
  
Mohs Hardness
7-7.5
  
5-6.5
  
Chemical Composition
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
  
SiO2 · nH2O
  
Staurolite and Opal Chemical Formula
While comparing Staurolite and Opal 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 Opal chemical formula.
- Chemical formula of Staurolite- (Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.
- Chemical formula of Opal- SiO2 · nH2O
Staurolite and Opal Specific Gravity
Another important criteria for qualitative analysis of gemstones is Staurolite and Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Staurolite and Opal Optical Properties during the identification of gemstone. Specific gravity of Staurolite is 1.98-2.25 whereas that of Opal is 1.98-2.25.