Opal and Obsidian Physical Properties

Opal and Obsidian Chemical Formula

While comparing Opal and Obsidian 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 Opal and Obsidian chemical formula.

• Chemical formula of Opal- SiO₂ · nH₂O
• Chemical formula of Obsidian- SiO2

Opal and Obsidian Specific Gravity

Another important criteria for qualitative analysis of gemstones is Opal and Obsidian Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Opal and Obsidian Optical Properties during the identification of gemstone. Specific gravity of Opal is 2.35-2.60 whereas that of Obsidian is 2.35-2.60.