Black Opal and Afghanite Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.97-2.22
  
2.55-2.65
  
Fracture
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
  
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
  
Cleavage
Not Available
  
Perfect {10 1 0}
  
Mohs Hardness
6-6.5
  
5.5-6
  
Chemical Composition
SiO 2 + H 2OUlrich Henn and Claudio C.
  
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
  
Black Opal and Afghanite Chemical Formula
While comparing Black Opal and Afghanite 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 Black Opal and Afghanite chemical formula.
- Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
- Chemical formula of Afghanite- (Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
Black Opal and Afghanite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Black Opal and Afghanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Black Opal and Afghanite Optical Properties during the identification of gemstone. Specific gravity of Black Opal is 2.55-2.65 whereas that of Afghanite is 2.55-2.65.