Black Opal and Common Opal Physical Properties

Black Opal and Common Opal Chemical Formula

While comparing Black Opal and Common Opal 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 Common Opal chemical formula.

• Chemical formula of Black Opal- SiO 2 + H 2OUlrich Henn and Claudio C.
• Chemical formula of Common Opal- SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)

Black Opal and Common Opal Specific Gravity

Another important criteria for qualitative analysis of gemstones is Black Opal and Common Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Black Opal and Common Opal Optical Properties during the identification of gemstone. Specific gravity of Black Opal is 1.98-2.50 whereas that of Common Opal is 1.98-2.50.