First of all, the sapphire used in the watch mirror and the case of a clock is a collective term, which is definitely different from the jewelry that people usually understand—natural sapphire. "Sapphire" is just a name, the main component of alumina, alumina is white, but white can not be used as the surface, it must be transparent, so a small amount of pure magnesium oxide, lanthanum trioxide and other additives are added, sapphire watch case，and continuous isostatic pressing is used. , Atmosphere sintering or hot pressing sintering, strictly controlled crystal grain size and made.
Because the sapphire crystal and case in the clock are not made of natural sapphire, but synthetic sapphire. Not only is the sapphire crystal and case not using natural sapphire, many watches also use synthetic rubies inside. Even if someone really uses natural sapphire (basically impossible), the color of natural sapphire is ever-changing. It can be called the most successful pretender in the world of colored gemstones: sapphire: In addition to the literal blue corundum gemstone, it can also be white, Yellow, pink, orange-orange, purple, green, etc. These colored sapphires are collectively referred to as colored sapphires. Even if it’s really blue, it’s usually not clear
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