It will involve the melting in the raw compound employing oxyhydrogen flame and the crystallisation of the melted droplets to kind a cylinder. Graded 9 on the Mohs-hardness scale (graded 1-10), the resulting sapphire crystals are virtually scratch-evidence and really tricky, making certain an unhindered vision at all times. They https://www.watchesworld.com/top-10-dive-watches/