The silver water cup I bought at Baijia Yinfang when traveling to Yunnan was not used for a month but was found to be rusty. Is it fake?

You can use a few small methods to identify the authenticity of a silver cup:

If your silver cup is a silver-plated cup, then its inner wall will be special. Smooth, just like the silver bracelets we usually wear (silver bracelets usually use electroplating to achieve a bright surface). If it is sterling silver, even if it has been polished, it will feel a bit scratchy.

You can use a magnet to attach to the surface of the silver liner. Because silver is not magnetic and the shell of your silver cup is not made of metal, you can use this method.

Let’s popularize why silver cups oxidize?

Silver is the most reactive of all metals and is easily oxidized and sulfurized. Silver oxide is brown, and of course it turns black when accumulated thickly, while silver sulfide is black. One of the important factors in the oxidation of silver is that there is a great affinity between silver ions and sulfide ions, which easily produces chemical reactions. The result of the reaction is that silver sulfide is produced on the silver surface. Because silver sulfide is gray-black, as the silver sulfide As the concentration increases, the surface color of silver gradually changes from white to yellow to gray and finally to black.

Remarks: No matter which cleaning method is used, the last step is to clean the silver cup with clean water and dry it with a dry cloth. If there is still water quality, it will accelerate its oxidation rate.