Do you know what a table mirror is？

The watch mirror is the transparent lens on the surface of the watch, also called watch glass, which is used to protect the dial of the watch. In addition, watch mirrors can be divided into three categories: plastic mirrors, quartz glass mirrors, and sapphire mirrors according to their materials. The rubber lens is relatively not afraid of falling, and the sapphire crystal is the most wear-resistant.

The appearance of mineral crystal glass, synthetic glass and sapphire crystal glass are very similar, but they are three completely different substances. The main differences are as follows:

1. Different materials: Mineral crystal glass is a crystal of silica, synthetic glass is only a molten mixture containing silica, and sapphire crystal glass is aluminum oxide with impurities such as iron oxide and titanium oxide removed.

2. Different prices: Sapphire crystal glass has the highest price, followed by mineral crystal glass, and the cheapest is synthetic glass.

3. Different hardness: Sapphire crystal glass has the highest hardness of Mohs 9, while mineral crystal glass is crystalline, and it also has a higher hardness of Mohs 7. The hardness of synthetic glass is lower, which is 5.5 on the Mohs scale.

4. Different processing technology: Synthetic glass can be formed by heat casting. Which can save materials, labor and cost. However, Mineral crystal glass and synthetic crystal glass are crystals. They cannot be reversed after being heated and melted. Therefore, hot casting cannot be used, but cold working methods such as cutting and grinding can only be used.

The sapphire crystal glass is made of crystal powder heated above 2000°C. The sapphire block it forms is cut into exquisite slices with extremely high precision, and then trimmed and polished to be used as watch glass.

In order to better identify these watch mirrors, we can use this simple method to identify. Firstly, you can tap your finger on the mirror to listen to the sound carefully. Synthetic glass mirrors, will make a sound like plastic, while the sound of glass is thicker. Secondly, from the perspective of weight, the acrylic mirror is the lightest and the sapphire mirror is the heaviest. Since sapphire has a very good thermal conductivity, when you touch it with your hands, there will be a cold feeling.

Since the sapphire mirror surface is much smoother than the mirror surfaces of the other two materials, if you drop a drop of water on the sapphire mirror surface, the water droplets will not spread easily, while the other materials will disperse into one piece.