It will involve the melting with the Uncooked material employing oxyhydrogen flame along with the crystallisation from the melted droplets to form a cylinder. Graded 9 around the Mohs-hardness scale (graded 1-10), the resulting sapphire crystals are practically scratch-evidence and very challenging, making certain an unhindered eyesight all the time. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/