It entails the melting in the raw substance utilizing oxyhydrogen flame as well as the crystallisation with the melted droplets to sort a cylinder. Graded 9 around the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are pretty much scratch-proof and very hard, ensuring an unhindered vision all the time. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/