While comparing Cordierite and Gedrite 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 Cordierite and Gedrite chemical formula.
Another important criteria for qualitative analysis of gemstones is Cordierite and Gedrite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Cordierite and Gedrite Optical Properties during the identification of gemstone. Specific gravity of Cordierite is 3.15-3.259 whereas that of Gedrite is 3.15-3.259.