When it comes to choosing the best pick among Gems for Capricorn gemstones, Onyx is known to be a popular choice!Physical properties of Onyx include its hardness, gravity, fracture, cleavage, etc. For any gemstone crystal, Onyx 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. Onyx cleavage is nothing but the plane across which the crystal splits during cutting. Onyx cleavage is Indiscernible,and specific gravity of Onyx is 2.55-2.70.
The physical properties of Onyx, 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 Onyx is represented by SiO2.