It includes the melting from the raw substance working with oxyhydrogen flame as well as the crystallisation in the melted droplets to variety a cylinder. Graded 9 to the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are nearly scratch-proof and really difficult, guaranteeing an unhindered vision all the time. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/