While comparing Sapphire and Agate 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 Sapphire and Agate chemical formula.
Another important criteria for qualitative analysis of gemstones is Sapphire and Agate Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sapphire and Agate Optical Properties during the identification of gemstone. Specific gravity of Sapphire is 2.60-2.64 whereas that of Agate is 2.60-2.64.