It involves the melting with the raw material applying oxyhydrogen flame and also the crystallisation from the melted droplets to form a cylinder. Graded nine around the Mohs-hardness scale (graded one-ten), the resulting sapphire crystals are pretty much scratch-evidence and very difficult, making sure an unhindered eyesight always. Its excellent https://www.watchesworld.com/top-10-dive-watches/