It entails the melting with the Uncooked substance using oxyhydrogen flame along with the crystallisation with the melted droplets to sort a cylinder. Graded 9 on the Mohs-hardness scale (graded 1-ten), the ensuing sapphire crystals are virtually scratch-proof and really hard, making certain an unhindered eyesight constantly. We advise that https://www.watchesworld.com/top-10-dive-watches/