Chow Tai Fook's gold chain is made of gold. On May 4, 20 16, the Regulations and Naming Methods for Precious Metals in Jewelry approved by the National Standardization Administration came into effect, which stipulated the purity of gold. Even gold ornaments with a purity of 999‰ can only be called pure gold, and cannot be marked with thousands of pure gold.

Pure gold jewelry is also called 99% gold, 10% gold and pure gold because its gold content is above 99% and the highest can reach 99.99%.

In order to overcome the shortcomings of gold, such as high price, low hardness, single color, easy wear and exquisite pattern, some other metal elements are usually added to pure gold to increase the hardness of jewelry gold, change its color tone and lower its melting point.

In this way, gold alloy jewelry with different fineness and obviously different gold content appeared, named carat.

Gold identification method

According to the different luster and color of gold, pure gold, k gold, real gold and fake gold can be roughly distinguished. In other words, red and yellow gold is the best, with a purity of over 95%, a positive yellow purity of about 80% and a cyan yellow purity of about 70%.

Yellow is light gray, and the fineness is about 50%. So there is the formula of seven green, eight yellow, nine five red, yellow and white with gray and half gold. For jewelry that has been hidden for a long time, there is a saying that copper turns green, silver turns black and gold never changes color.

The density of gold is 19.32g/cm3, which is about twice as heavy as that of silver, lead and tin with the same volume. According to the formula, the quality of a gold ornament is equal to the density of a gold ornament.

Calculate the density of the measured gold jewelry. If the density is about 19.32g/cm3, it is pure gold or relatively pure gold, otherwise it is impure gold or colored gold. This method is not destructive to jewelry.