It includes the melting from the raw substance using oxyhydrogen flame plus the crystallisation on the melted droplets to kind a cylinder. Graded 9 around the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are pretty much scratch-proof and very really hard, guaranteeing an unhindered vision all of the time. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/