1, for gold jewelry, we can identify it from two aspects, one is to weigh it, and the other is to look at the color. Compared with brass, gold feels heavy and oppressive in the palm of your hand, because the specific gravity of gold is 19.32g/cm3, while that of brass is only 8.9g/cm3, the former is more than twice that of the latter. The yellower the color of gold, the better the fineness. If it is red, it contains high copper impurities. If it is white, the silver-containing impurities are high and the fineness of gold is low.

2.k gold is an alloy of gold and other metals, such as silver, copper, zinc and nickel. The gold content of 18K gold is 75%, and the total content of other metals is 25%. Manufacturers can make K gold into various colors according to different proportions of other metals, such as yellow-green, black, green and white. Some people pretend that red-green 18K gold is pure gold, and white 18K gold is platinum.

There are two simple ways to distinguish K gold from pure gold, one is hardness and the other is elasticity. K gold is harder than pure gold. Pure gold is purer and softer, and the mark can be bitten out with teeth, but K gold is not. K gold ring fell to the ground, which has a strong rebound, while the foot gold ring fell to the ground, which did not show such performance.

Using gold-plated jewelry as gold jewelry is another means of counterfeiting. Jewelry made of brass is plated with a thin layer of gold, and its value is very low. Because it is difficult to pass off as pure gold, some people sell it as 18K gold, and the imprint of jewelry is marked with "18KGP". The appearance color of this kind of gold-plated jewelry is different from real gold, which is obviously reddish and lacks gold, and the appearance can also be distinguished.

4. Jewelry made of metallic nickel is passed off as platinum jewelry. Metallic nickel is the material for making one-dollar coins. It is white and non-oxidizing, and looks like the color of platinum. However, the specific gravity of platinum is 2 1.4g/cm3, while the specific gravity of nickel is only 8.85g/cm3, so the sense of heaviness is obviously different.

5, silver and platinum, although the appearance color is similar, but it is easier to identify. The specific gravity of silver is 10.5g/cm3, which is only 1/2 of platinum. In addition, pure silver is soft and easy to oxidize, and will turn black after being placed in the air for a period of time, while platinum is different, harder and will not oxidize.