Sapphire glass is what we call sapphire. It is synthetic. Sapphire watch glasses are generally made of sapphire glass after processing and upgrading. It can be in line with the jewelry industry. Most watch lenses are made of sapphire. It takes the fine and precise alumina powder as the raw material, and then condenses into crystal blocks in the corresponding high-temperature furnace. After countless times of manual processing, its hardness is quite high, second only to diamond, which is complete with steel. Finally, it is made into a surface lens composed of sapphire components. This surface lens can prevent scratching, falling and corrosion, and can resist strong water pressure when swimming shallow under the water; Sapphire is generally blue. Why is it transparent? It is not sapphire in the traditional sense. It is a kind of crystal glass, which is made manually. In addition to being used on the watch mirror, there are some mobile phone windows that can be used as it.