925 silver jewelry is 92.5% pure silver and then added 7.5% alloy, add alloy in order to make silver luster, brightness and hardness have improved. And since 1851, when Tiffany launched its first set of silver jewelry with a silver content of 92.5%, 925 silver has become popular, so it is now 925 as the standard for identifying whether it is sterling silver jewelry.
925 silver jewelry after polishing to show a very beautiful metallic luster, but also has a certain hardness, can be inlaid with gems, made into high-grade jewelry.
990 Silver, is the content of 99% Sterling Silver and 1% of the alloy, because of its hardness is not enough, made into jewelry easy to deform, so few manufacturers use it to make jewelry, and 990 silver in the industrial use of a relatively wide range. 800 Silver is a content of 80% Sterling Silver added 20% of the alloy, because the purity of silver more are low easier to oxidize, so manufacturers rarely use it to make jewelry.
It is only reassuring to pass the silver jewelry that you have tested. Although the raw materials of silver are very cheap, but there will be some manufacturers in the silver ornaments mixed with cadmium, iron, copper and other cheaper metals. Cadmium is harmful to the human body and is not allowed to be mixed in jewelry according to regulations. Manufacturers do this mainly to reduce costs and achieve higher profits. Copper wire is mainly mixed in the silver lock to do the middle of the support frame, according to the state regulations in the Silver lock support frame should also be silver. Because the copper wire is hidden in the silver lock, so the consumer can not see at all, only in the jewelry testing time to destroy it to see its true face. Only by waiting for a long time, inside the copper rust oozing out, consumers can find.