It will involve the melting in the raw material utilizing oxyhydrogen flame as well as crystallisation on the melted droplets to form a cylinder. Graded 9 to the Mohs-hardness scale (graded 1-10), the resulting sapphire crystals are almost scratch-proof and really tough, making sure an unhindered eyesight at all times. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/