It consists of the melting from the raw material utilizing oxyhydrogen flame and also the crystallisation from the melted droplets to type a cylinder. Graded 9 to the Mohs-hardness scale (graded 1-10), the ensuing sapphire crystals are almost scratch-proof and very hard, making sure an unhindered vision all the time. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/