It involves the melting of your raw material using oxyhydrogen flame and also the crystallisation in the melted droplets to form a cylinder. Graded 9 within the Mohs-hardness scale (graded one-ten), the resulting sapphire crystals are virtually scratch-evidence and really difficult, ensuring an unhindered eyesight constantly. Linkedin set this cookie https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/