While comparing Topaz and Eilat stone 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 Topaz and Eilat stone chemical formula.
Another important criteria for qualitative analysis of gemstones is Topaz and Eilat stone Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Topaz and Eilat stone Optical Properties during the identification of gemstone. Specific gravity of Topaz is Not Available whereas that of Eilat stone is Not Available.