It will involve the melting with the raw compound making use of oxyhydrogen flame and also the crystallisation from the melted droplets to form a cylinder. Graded nine within the Mohs-hardness scale (graded 1-10), the resulting sapphire crystals are virtually scratch-proof and really challenging, ensuring an unhindered eyesight constantly. Photo: https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/