While comparing Sonolite and Sillimanite 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 Sonolite and Sillimanite chemical formula.
Another important criteria for qualitative analysis of gemstones is Sonolite and Sillimanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Sonolite and Sillimanite Optical Properties during the identification of gemstone. Specific gravity of Sonolite is 3.20-3.26 whereas that of Sillimanite is 3.20-3.26.