It consists of the melting on the raw material making use of oxyhydrogen flame along with the crystallisation on the melted droplets to sort a cylinder. Graded nine over the Mohs-hardness scale (graded 1-10), the resulting sapphire crystals are just about scratch-proof and very tough, ensuring an unhindered vision continually. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/