It involves the melting in the raw material applying oxyhydrogen flame along with the crystallisation of the melted droplets to form a cylinder. Graded nine on the Mohs-hardness scale (graded 1-10), the ensuing sapphire crystals are almost scratch-evidence and really tough, guaranteeing an unhindered eyesight continually. We advise that each https://www.watchesworld.com/top-10-dive-watches/