It involves the melting with the raw material working with oxyhydrogen flame as well as the crystallisation on the melted droplets to sort a cylinder. Graded 9 about the Mohs-hardness scale (graded 1-ten), the resulting sapphire crystals are just about scratch-proof and very hard, guaranteeing an unhindered eyesight constantly. Linkedin https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/