It entails the melting of your raw material utilizing oxyhydrogen flame plus the crystallisation in the melted droplets to variety a cylinder. Graded nine within the Mohs-hardness scale (graded 1-10), the ensuing sapphire crystals are pretty much scratch-evidence and very tough, guaranteeing an unhindered vision all the time. We propose https://www.watchesworld.com/top-10-dive-watches/