It consists of the melting on the raw substance making use of oxyhydrogen flame as well as crystallisation with the melted droplets to kind a cylinder. Graded 9 to the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are virtually scratch-evidence and really really hard, ensuring an unhindered vision always. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/