Opal and Realgar Physical Properties
Tenacity
BrittleWalter Schumann
  
Not Available
  
Solubility
hot salt water
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.98-2.25
  
3.56
  
Fracture
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Brittle
  
(e.g. graphite).
  
Cleavage
None
  
{010} Good
  
Mohs Hardness
5-6.5
  
Not Available
  
Chemical Composition
SiO2 · nH2O
  
AsSMichael OâDonoghue , Gems, Sixth Edition (2006)
  
Opal and Realgar Chemical Formula
While comparing Opal and Realgar 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 Realgar chemical formula.
- Chemical formula of Opal- SiO2 · nH2O
- Chemical formula of Realgar- AsSMichael OâDonoghue , Gems, Sixth Edition (2006)
Opal and Realgar Specific Gravity
Another important criteria for qualitative analysis of gemstones is Opal and Realgar Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Opal and Realgar Optical Properties during the identification of gemstone. Specific gravity of Opal is 3.56 whereas that of Realgar is 3.56.