1 specific gravity test method: there is a specific gravity liquid on the market to measure the specific gravity of precious stones; We can use a liquid with a specific gravity of 3.32 to test the authenticity of diamonds. The specific gravity of natural diamonds is 3.52, and all natural diamonds will sink when placed in specific gravity water, so any gem floating on specific gravity water can be sure not to be a diamond.

Penetration observation method: the high refractive index of diamond, the higher the refractive index, the stronger the reflection and the lower the relative perspective. You can prepare a piece of paper with a straight line. The two unknown diamonds to be measured face down and cover a straight line. If you can see a straight line under a diamond, it is definitely not a natural diamond.

3 lipophilic method: diamonds have an "oil absorption" effect on grease, while counterfeit diamonds do not have this characteristic. Rub the diamond on your face and rub it with your thumb. Your thumb will feel sticky and not easy to slip, while fake diamonds will make your thumb feel slippery.

Breathing test: natural diamond has good heat transfer ability and fast heat dissipation. Put the diamond to be tested close to your mouth, breathe gently, and let the diamond to be tested be covered with a layer of light fog. At this time, watch the evaporation of diamond fog immediately. If it is a natural diamond, the fog will disperse immediately, otherwise, the fog will stay on the fake diamond for a while before dispersing.

5 Size and weight: 1 carat The diameter of natural diamond is about 6.50 mm (0.65 cm). Most fake diamonds are always far from natural diamonds under the same weight of 1 carat.