Everyone knows diamonds. Has anyone heard of CVD high imitation diamonds? This is a product that is enough to be fake, and it is difficult to distinguish between the naked eye and the ordinary identification instrument. It can only be identified by precision instruments. How should consumers prevent risks?
Recently, the National Jewelry Quality Appraisal Center (NGTC) found two batches of “Chemical Vapor Deposition†synthetic diamonds, hereinafter referred to as CVD diamonds, purchased from Hong Kong, which are difficult to identify with the naked eye and ordinary instruments. Jewelry appraisal experts suggest that consumers must look at the certificate and ask for a business invoice to buy diamonds in case they are deceived.
What people usually call a diamond is a natural diamond. The quality of a diamond depends on the diamond's evaluation standard 4C, ie color, clarity, cut and weight. The whiter the better, the less the inner inclusion is, the better. For example, the same 1 carat natural diamond, the clarity, color, cut, the price will be several times or even dozens of times.
The so-called CVD synthetic diamond is a high-quality diamond formed by high-purity heating and purification of a low-quality natural diamond using high-purity methane, hydrogen, and nitrogen.
The two batches of CVD synthetic diamonds tested by the National Jewelry Quality Appraisal Center have a weight of 0.5 carats, and the color is mostly yellowish white. It is 4 grades different from the highest level of diamond color, and the highest level of clarity is also lagging. Two levels. Ms. Yang, a jewelry appraiser at Peking University's Gemological Appraisal Center, said that it is difficult to identify such CVD synthetic diamonds by ordinary methods.
Ms. Yang: CVD synthesis and high temperature and high pressure synthesis, you can not identify it with ordinary identification methods. There is usually a thermal conductivity meter, but the synthetic thermal conductivity point is also small.
Mr. Luo, Director of the National Jewelry Quality Supervision and Inspection Center, said that the only way to identify CVD synthetic diamonds is to use more sophisticated instruments to detect:
Mr. Luo: It can only be used in the laboratory specialized in jewelry identification. The naked eye and the general test can't be identified. It can only be measured by some instruments.
Natural diamonds are very rare and expensive, but CVD synthetic diamonds are easy to manufacture, and their prices are far cheaper than natural diamonds. Coupled with consumers' illegibility, CVD synthetic diamonds are shoddy and deceive consumers. Occurs, thus greatly disrupting the order of the natural diamond market.
How can consumers be deceived in the mixed diamond market? Mr. Luo suggested that you must see the certificate of diamond purchase before you can purchase it.
Mr. Luo: When you buy a diamond, you must have a certificate issued by a third party. If you have a certificate on the certificate, you must re-name it to see if it weighs. The third one is to see if the photo in the certificate is in kind. In accordance with the standards, all quality supervision agencies have to provide a website to query, or the phone can also check to see if the certificate is true or false.
In addition, letting merchants invoice is also a good way to protect consumer rights:
Mr. Luo: If you don't feel comfortable after buying, you can open an invoice when you buy it. The invoice should write out what this is, and let the mall invoice be the best quality guarantee.
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