Watch mirror, that is the transparent lens on the watch surface, also called watch glass, is used to protect the watch surface (dial). Table mirror according to the material can be divided into synthetic glass mirror, mineral crystal glass mirror, sapphire crystal glass mirror and other three categories. Synthetic glass mirror is not afraid of falling, sapphire mirror is the most wear-resistant.
What are the glass materials for watches?
Sapphire crystal: stable physical and chemical properties, hardness is second only to diamond, it can solve scratch, aging, corrosion and other problems, but fragile. (usually used for high-end watches)
Organic glass: synthetic glass, commonly known as acrylic, easy to scratch, but good toughness, not brittle. (mostly used for low-end watches)
Mineral glass: good abrasion resistance, but the anti vertical combat ability in the sapphire glass, so many military uses it as the table mirror. (used for medium and low end tables)