While comparing Chiastolite and Nepheline 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 Chiastolite and Nepheline chemical formula.
Another important criteria for qualitative analysis of gemstones is Chiastolite and Nepheline Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Chiastolite and Nepheline Optical Properties during the identification of gemstone. Specific gravity of Chiastolite is 2.55-2.65 whereas that of Nepheline is 2.55-2.65.