It includes the melting in the raw compound applying oxyhydrogen flame as well as crystallisation with the melted droplets to sort a cylinder. Graded 9 around the Mohs-hardness scale (graded one-10), the resulting sapphire crystals are just about scratch-evidence and very tricky, ensuring an unhindered eyesight always. Photo: HICONSUMPTION It https://www.watchesworld.com/the-most-coveted-watches-in-the-uk/