It includes the melting from the raw compound utilizing oxyhydrogen flame as well as the crystallisation on the melted droplets to form a cylinder. Graded nine to the Mohs-hardness scale (graded one-ten), the ensuing sapphire crystals are pretty much scratch-proof and really hard, ensuring an unhindered vision always. Practical cookies https://www.watchesworld.com/top-10-dive-watches/