Black Opal and Almandine Physical Properties
Tenacity
Not Available
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.97-2.22
  
3.95-4.30
  
Fracture
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
  
Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
  
Cleavage
Not Available
  
none
  
Mohs Hardness
6-6.5
  
7-7.5
  
Chemical Composition
SiO 2 + H 2OUlrich Henn and Claudio C.
  
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
  
Black Opal and Almandine Chemical Formula
While comparing Black Opal and Almandine 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 Almandine chemical formula.
- Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
- Chemical formula of Almandine- Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
Black Opal and Almandine Specific Gravity
Another important criteria for qualitative analysis of gemstones is Black Opal and Almandine Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Black Opal and Almandine Optical Properties during the identification of gemstone. Specific gravity of Black Opal is 3.95-4.30 whereas that of Almandine is 3.95-4.30.