However, the possibility of certificate fraud is not ruled out. If you really want to buy it, you can keep the invoices and documents after purchase and take the jewelry to the jewelry appraisal center for appraisal.
Extended data
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 liquid can be sure not to be a diamond.
2. 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 tested 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 "oil absorption" effect on grease, while fake diamonds do not have this characteristic. Rub the diamond with a little oil on your face and rub it with your thumb, which will feel sticky and not easy to slip, while the fake diamond will make your thumb feel very slippery.
4. 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 natural diamond is about 6.50 mm (0.65 cm) in diameter. Most fake diamonds are always far from natural diamonds under the same weight of 1 carat.
6. Artificial zirconia: high hardness and good refraction, but it will reflect more colored light when rotating, which is obviously different from the genuine product that only reflects weak yellow and blue light when rotating.
7. Hardness test: Diamond is the hardest natural substance known. Nothing can be found on the diamond. If it can be traced, it's definitely not a diamond.
8. Observe the reflected light: With a magnifying glass, you can observe that the waist of the diamond presents a very fine matte shape, and the reflected light shines. This characteristic of diamonds is unique.
Refer to Baidu Encyclopedia-Diamond Identification