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