It will involve the melting of the raw substance utilizing oxyhydrogen flame and also the crystallisation from the melted droplets to form a cylinder. Graded nine to the Mohs-hardness scale (graded one-ten), the resulting sapphire crystals are virtually scratch-evidence and really tough, making certain an unhindered vision at all times. https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/