It consists of the melting on the raw compound employing oxyhydrogen flame as well as the crystallisation in the melted droplets to type a cylinder. Graded nine on the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are almost scratch-proof and very difficult, guaranteeing an unhindered vision all the time. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/