While comparing Sugilite and Sard 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 Sugilite and Sard chemical formula.
Another important criteria for qualitative analysis of gemstones is Sugilite and Sard Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sugilite and Sard Optical Properties during the identification of gemstone. Specific gravity of Sugilite is 2.58-2.63 whereas that of Sard is 2.58-2.63.