Boulder Opal and Calcite Physical Properties
Tenacity
Not Available
  
Brittle
  
Solubility
Not Available
  
Soluble
  
Durability
Not Available
  
Not Available
  
Specific Gravity
1.98-2.25
  
2.67-2.73
  
Fracture
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
  
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
5-6.5
  
3
  
Chemical Composition
SiO 2 + H 2OUlrich Henn and Claudio C.
  
CaCO 3Ulrich Henn and Claudio C.
  
Boulder Opal and Calcite Chemical Formula
While comparing Boulder 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 Boulder Opal and Calcite chemical formula.
- Chemical formula of Boulder Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
- Chemical formula of Calcite- CaCO 3Ulrich Henn and Claudio C.
Boulder Opal and Calcite Specific Gravity
Another important criteria for qualitative analysis of gemstones is Boulder Opal and Calcite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Boulder Opal and Calcite Optical Properties during the identification of gemstone. Specific gravity of Boulder Opal is 2.67-2.73 whereas that of Calcite is 2.67-2.73.