Dongzhu in freshwater pearls is better than Nanzhu. When choosing pearls, two beads rub, and the feeling of rustling is natural, the feeling of smoothness is artificial, or scraping with a needle is false. When choosing pearls, you should choose ones with soft colors, high gloss and large and round particles. (Of course, good tower beads are also expensive. ) Look at the pearl surface carefully, there are no pinholes and trachoma. Black and blue are rare, purple is medium, and pink and white are common. Always wipe pearl ornaments in summer, because sweat will corrode the surface of pearls and make them dark and yellow. When scrubbing pearls, avoid using alkaline detergent, and it is better to use clean water. Pearls have been placed for a long time, so they should be soaked in mineral water for several hours to avoid lack of water and loss of luster. Even the best pearls can only be used for a hundred years.