While comparing Chlorastrolite and Alexandrite 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 Chlorastrolite and Alexandrite chemical formula.
Another important criteria for qualitative analysis of gemstones is Chlorastrolite and Alexandrite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Chlorastrolite and Alexandrite Optical Properties during the identification of gemstone. Specific gravity of Chlorastrolite is 3.69-3.81 whereas that of Alexandrite is 3.69-3.81.