While comparing Dumortierite and Friedelite 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 Dumortierite and Friedelite chemical formula.
Another important criteria for qualitative analysis of gemstones is Dumortierite and Friedelite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Dumortierite and Friedelite Optical Properties during the identification of gemstone. Specific gravity of Dumortierite is 3.06-3.19 whereas that of Friedelite is 3.06-3.19.