It consists of the melting from the raw substance using oxyhydrogen flame and also the crystallisation from the melted droplets to kind a cylinder. Graded nine within the Mohs-hardness scale (graded 1-10), the resulting sapphire crystals are pretty much scratch-proof and really really hard, making sure an unhindered eyesight constantly. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/