(2) Silver

Chemical element symbol: Ag; atomic number: 47; melting point: 961.93℃; boiling point: 2210 ℃; Mohs hardness: 2.7.

Silver has the best electrical conductivity among all metals, and its thermal conductivity is also excellent. Additionally, silver has good elasticity, second only to gold. Using modern technology, 1 g of silver can be drawn into fine wire of 1800~2000 m and wrapped into silver foil that is 0.025 mm thick, making it very convenient for jewelry design and production. Moreover, silver has a relatively low melting point. Silver generally emits a pure white and pleasing metallic luster, with a reflectivity of up to 94%, making it the closest precious metal to pure white.

The chemical properties of silver are relatively stable; it does not react with oxygen at room temperature, and its color remains unchanged in the air. However, compared to gold, it is still considered an easily oxidizable metal, forming black silver oxide upon oxidation. When silver comes into contact with sulfur-containing substances or is exposed to gases containing sulfur dioxide or hydrogen sulfide, it will react with sulfur to form black silver sulfide. Silver can also react with arsenic to form black silver arsenide, which has historically been used to test whether food contains arsenic (arsenic oxide).

Silver products sold on the market undergo plating processes to make silver less prone to oxidation, usually plated with nickel or gold; silver tableware generally does not require plating, only regular cleaning and maintenance. No electroplated silver products are placed in the air for a long time or worn after not often cleaned up; the surface may produce a black layer. You can use a clean silver polishing cloth to wipe or a soft cotton cloth smeared with toothpaste to wipe, and then rinse with water; the black layer will generally disappear, but it is also available to clean up the professional silver washing water to reduce the loss of the surface of the ornaments.

As a member of the jewelry metal family, silver has excellent properties and a very beautiful appearance, making it very popular. Many jewelry pieces are made from silver, and China is also a major consumer of silver.

• Colored K gold: Designers often feel that the colors of precious metals are limited when creating works, with the common ones being gold and white. Therefore, the emergence of colored K gold creates more jewelry art possibilities. Most colored K gold jewelry uses colored 18K gold. In colored 18K gold, the proportions of components other than 750‰ gold can be adjusted to present different colors.

Red K gold, also known as rose gold—gold, silver, copper can be combined to create red and light red K gold; green K gold, and gold and aluminum make bright red karat gold—adding a small amount of cadmium to the gold, silver, and copper alloy can produce green K gold; blue K gold—adding cobalt to the surface of a gold and iron alloy can achieve this; white K gold—adding nickel or palladium to a gold-copper alloy can produce this; black K gold—adding a high concentration of iron to gold can achieve this, with the black 14K gold ratio being gold 58.3%, iron 41.7%.

Some colored K gold is made using surface plating rather than smelting, making the color prone to wear. Some white 18K gold on the market is made by plating nickel or rhodium, with palladium on the surface of 18K gold. After wear, the jewelry turns yellow, revealing the original color of 18K gold. Therefore, it is necessary to consult the supplier clearly when purchasing to avoid making a wrong choice.