Opal and Anhydrite Physical Properties
Tenacity
BrittleWalter Schumann
  
Brittle
  
Solubility
hot salt water
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.98-2.25
  
2.90-2.98
  
Fracture
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Brittle
  
Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
  
Cleavage
None
  
Rare tabular and prismatic crystals. Usually occurs as fibrous, parallel veins that break off into cleavage fragments.
  
Mohs Hardness
5-6.5
  
3.5
  
Chemical Composition
SiO2 · nH2O
  
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
  
Opal and Anhydrite Chemical Formula
While comparing Opal and Anhydrite 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 Opal and Anhydrite chemical formula.
- Chemical formula of Opal- SiO2 · nH2O
- Chemical formula of Anhydrite- CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
Opal and Anhydrite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Opal and Anhydrite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Opal and Anhydrite Optical Properties during the identification of gemstone. Specific gravity of Opal is 2.90-2.98 whereas that of Anhydrite is 2.90-2.98.