Common Opal and Calcite Physical Properties
Tenacity
Not Available
  
Brittle
  
Solubility
Not Available
  
Soluble
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.98-2.50
  
2.67-2.73
  
Fracture
Conchoidal, Conchoidal, Gemstones of the world (2001)
  
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
  
Cleavage
Not Available
  
Perfect on [10 1 1] three directions with angle of 74° 55
  
Mohs Hardness
5.5-6.5
  
3
  
Chemical Composition
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
  
CaCO 3Ulrich Henn and Claudio C.
  
Common Opal and Calcite Chemical Formula
While comparing Common Opal and Calcite 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 Common Opal and Calcite chemical formula.
- Chemical formula of Common Opal- SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
- Chemical formula of Calcite- CaCO 3Ulrich Henn and Claudio C.
Common Opal and Calcite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Common Opal and Calcite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Common Opal and Calcite Optical Properties during the identification of gemstone. Specific gravity of Common Opal is 2.67-2.73 whereas that of Calcite is 2.67-2.73.