When it comes to choosing the best pick among Blue Gemstones gemstones, Blue John is known to be a popular choice!Physical properties of Blue John include its hardness, gravity, fracture, cleavage, etc. For any gemstone crystal, Blue John Optical Properties are responsible for imparting various physical properties to its structure. Knowledge of these properties is equally important to gem-cutters as well as to consumers. Blue John cleavage is nothing but the plane across which the crystal splits during cutting. and specific gravity of Blue John is 3.00-3.25.
The physical properties of Blue John, in fact, are imparted by the chemical composition of its individual molecule. The reactivity or inertness of the crystal is solely governed by its chemical structure. Chemical composition of Blue John is represented by CaF 2Michael OâDonoghue , Gems, Sixth Edition (2006).