It involves the melting on the raw compound using oxyhydrogen flame as well as the crystallisation of the melted droplets to kind a cylinder. Graded nine to the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are pretty much scratch-proof and really tricky, ensuring an unhindered eyesight constantly. Be sure https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/