Silver is one of the precious metals, with the symbol Ag, which is widely circulated among the people and once circulated as currency. Silver is silvery white with a relative density of 10.49 and a melting point of (96 1℃). Easy to smelt, hardness 2.5, strong ductility, insoluble in alkali and most organic acids, soluble in nitric acid and hot sulfuric acid, and turns brown Ag2S after combining with sulfur dioxide in air. It has been used to make jewelry since ancient times, and the price is moderate, usually with inexpensive gems.
The purity of silver is expressed in parts per thousand. Foot silver: the silver content is not less than 99, and the imprint is foot silver or S990 plus silver 990. 925 Silver: The silver content is not less than 92.5, and the stamp is S925 or Silver 925. Since Tiffany introduced the first set of silverware with 925% silver in 185 1, 925 silver has become the main force of silverware in the market. Due to the addition of 7.5% copper, the hardness and luster of silver are improved.
The pure silver belt is soft and easy to deform. When making silver ornaments, a certain alloy is usually added to silver to increase the hardness of silver, which is more suitable for making jewelry. Most of the silver ornaments made by European goldsmiths are 925 silver, but some silver ornaments made by hand carving technology still use the international standard 1# pure silver with a silver content of 99.95% due to production needs.
Health care function of silver: silver has bactericidal effect, and food with silver tableware is not easy to ferment and turn sour; Silver compounds can treat burns and bandage wounds; Silver chopsticks can detect sulfur in food.