If the mirror of a watch is synthetic sapphire, sapphire glass is usually printed on the back cover of the watch, which is expressed in English as sapphire or sapphire crystal, but it is also common to use sapphire glass now.

2, scraping purlin method

That is, nail scratches on the mirror of the watch. If there is a sense of hysteresis, the material of the watch mirror is ordinary crystal. If it feels smooth and has no resistance, it is sapphire. Or, use a sharp metal object like a needle to scratch the most inappropriate place on the edge of the watch glass. It feels hard, and there is a feeling that metal objects are floating. The glass has no scratches. It's sapphire glass.

3. Drip method

Drop a drop of water directly on the watch mirror to see if the dropped water falls vertically, and the drop will not spread, so it can slide down slowly, usually made of sapphire. If this drop of water is scattered, it means that the watch mirror is ordinary crystal.

Extended data:

Sapphire glass generally refers to synthetic sapphire, which is quite different from the natural sapphire that people usually understand, and is generally used to make watch mirrors.

It, tungsten-titanium alloy and high-tech ceramics are all wear-resistant materials. Although these materials can resist wear, they cannot withstand strong impact, and some substances with the same or higher hardness (such as grindstone, granite surface, concrete wall and floor, etc. ) may scratch the surface of these materials.

Sapphire is the general name of corundum gemstones with other colors except ruby, and its main component is alumina (Al2O3). Sapphire glass refers to synthetic sapphire, which can be produced easily and cheaply in the laboratory, and its chemical composition and physical properties are the same as those of natural sapphire.

Baidu encyclopedia-sapphire glass