While comparing Elaeolite and Biotite 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 Elaeolite and Biotite chemical formula.
Another important criteria for qualitative analysis of gemstones is Elaeolite and Biotite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Elaeolite and Biotite Optical Properties during the identification of gemstone. Specific gravity of Elaeolite is 2.7-3.3 whereas that of Biotite is 2.7-3.3.