It entails the melting of your Uncooked material working with oxyhydrogen flame and the crystallisation with the melted droplets to kind a cylinder. Graded nine to the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are pretty much scratch-proof and really tough, ensuring an unhindered eyesight continually. Useful cookies Useful https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/