Traditionally making stone mirrors

It's not the composition that tells it whether it's crystal or glass.

The following is a copy of my personal answer, and the method of personal identification of crystals.

Regarding the crystal stone, the tea mirror mainly depends on the color, which is brown. In addition, look at the flocculent cotton fog in the lens, which is naturally easy to distinguish after a long time. The less flocs there are in the rock crystal, the deeper the color of the lens, and the greater the curvature of the lens (500 degrees to the end), the more valuable it is.

White crystals are difficult to distinguish, one is to look at cotton, the other is to touch. It should be noted that the hardness of the crystal is very high, so it will not appear on the lens, and several lines will not appear on the film for decades.

As for the artificial crystal stone, the color of the tea mirror is red, which is obviously not natural green tea color, and there is no flocculent cotton like hair.

Regarding the glass lenses, the color of the tea mirror is yellow, which is very nice. By the way, artificial crystal stone contains 38% metallic lead, which is harmful to human body. It is recommended not to bring it.

Remember not to judge whether it is crystal by the weight of the lens. Thick glass lenses are much heavier than crystal ones.

Welcome to ask questions