First of all, gold has a high density. Generally speaking, the same volume of metal objects, gold products are much heavier, too light products must be fakes; Secondly, gold and silver have small hardness, soft texture and strong ductility. If a metal object is lightly scratched on a gold and silver product, the dent is generally genuine and the scratch is fake; Thirdly, the chemical properties of gold and silver are relatively stable, especially gold, which is not easy to oxidize in air, while copper and iron products are easy to oxidize and rust. The color of gold remains unchanged in acidic solution, while copper products lose their luster when exposed to nitric acid. In the case of gold plating, the gold plating on the surface layer is easy to fall off, not only the falling part is easy to rust, but also the gold plating surface is easy to be covered by copper.
Of course, when ancient gold and silver wares were unearthed, some surfaces were covered with copper rust, especially silverware. This situation is due to the fact that gold and silver utensils come into contact with other corrosive copper before being unearthed, such as being buried with bronze utensils and being polluted by copper rust. Another reason is that the texture of most ancient silverware is copper alloy with certain components. When copper is oxidized and corroded, a layer of patina will form on silverware. However, in most of these cases, the original appearance of the vessel can be restored by rust removal. In addition, experienced people can also distinguish the authenticity of gold and silver objects by sound, taste, color and feel. However, it needs to accumulate rich practical experience.
In addition, unlike the forgery of ancient bronzes, jade articles and other utensils, the most common forgery of gold and silver utensils is the forgery of materials and textures, mostly for the purpose of seeking high profits. There are few forgers of chronology, which also leads to the lack of theoretical and practical experience, systematic research and experience summary in this field.
Pure gold (99.99% gold content) has soft texture, tooth marks, easy bending, golden color, purity and softness, and heavy hand feeling. The texture of K gold is slightly hard, there is no impression on the teeth, and the color is yellow with white, and with the decrease of K number, the white gradually increases and the yellow gradually becomes lighter. K gold is not as heavy as pure gold.
There are many kinds that are easily confused with gold, some are gilded and some are gilded. The following is a brief description of its various types:
Gold plating is plating a layer of gold on the surface of other metals by electroplating. The color is almost the same as real gold, golden and shiny, and it is difficult to recognize when it is new. However, the gold-plated feel is light, the texture is hard, the teeth are not printed, and it is easy to fade after being used for a long time. Some gold plating is not good, the color is red or white, or flowers.
Color gold refers to the 24K or 22K gold foil wrapped on other metal surfaces. If the k value of gold foil is too low, its softness is poor. Jinbao looks like real gold, glittering, not easy to fade, and it is difficult to distinguish between true and false. However, a careful observation of the dents, included angles, backs, etc. of jewelry will reveal that the gold foil is uneven and peeling. Because there are broken joints on it, we can see that the section of metal material is yellow outside and white inside. In addition, the feeling of gold plating is relatively light, the texture is pure gold and hard, the teeth are not printed, it is not easy to bend, and the gold foil is easy to peel off after being worn for a long time.
Copper yellow with red, false, dark luster, soft texture, light weight. Copper alloy (copper-tin alloy) is light in color, hard and light in quality, which will change color and make the skin black. References:
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