While comparing Vermeil and Boulder Opal 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 Vermeil and Boulder Opal chemical formula.
Another important criteria for qualitative analysis of gemstones is Vermeil and Boulder Opal Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Vermeil and Boulder Opal Optical Properties during the identification of gemstone. Specific gravity of Vermeil is 1.98-2.25 whereas that of Boulder Opal is 1.98-2.25.