While comparing Meionite and Allanite 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 Meionite and Allanite chemical formula.
Another important criteria for qualitative analysis of gemstones is Meionite and Allanite Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Meionite and Allanite Optical Properties during the identification of gemstone. Specific gravity of Meionite is 3.40-4.20 whereas that of Allanite is 3.40-4.20.