It involves the melting in the raw compound utilizing oxyhydrogen flame along with the crystallisation of the melted droplets to form a cylinder. Graded nine to the Mohs-hardness scale (graded 1-10), the ensuing sapphire crystals are virtually scratch-proof and really challenging, guaranteeing an unhindered vision all of the time. All https://www.watchesworld.com/top-10-dive-watches/