GC pure gold is pure gold with high purity, which is what we usually call pure gold. It contains more gold than the pure gold we usually wear. It is real gold. The purity of gold products is called "success" or "fineness" More than 200 years BC, the Greek mathematician Archimedes worried about judging whether a crown was made of pure gold. When he was taking a bath in the bathtub, he discovered what later generations called Archimedes' law of specific gravity: an object immersed in a liquid is subjected to upward buoyancy, and the buoyancy is equal to the weight of the liquid it displaces. Thereby successfully confirming whether the crown made by the king is made of pure gold. So, how to express the purity of gold? Theoretically, we call gold with a content of 100% 24K; ; Therefore, the calculation method is 100/24 (the national standard is in brackets): the national standard GB 1 1887-89 stipulates that the gold content per k (abbreviation of English carat and German carat, often written as "k") is 4. 16666%. 9k =100%/24 * 9 = 37.5% (375 ‰)14k =100%/24 *14 = 58.333% (585 ‰) is a sign of convenience. Set to 58.5%18k =100%/24 *18 = 75% (750 ‰) 22k =100%/24 * 22 = 91.60. But in reality, it is impossible to have 1 0,000% gold, so China stipulates that gold with a content of more than 99.6% (including 99.6%) can be called 24K gold. These kinds of K gold contents are general specifications of jewelry, and gold jewelry below 9K is not called gold jewelry according to national regulations. Thousands of gold with a gold content of not less than 999 is called thousands of gold, which is the highest value in jewelry color naming. The stamps are thousands of gold, 999 gold, 999 gold or g999 gold. The imprint of gold jewelry includes manufacturer's code, material and purity, such as X Gold 990, XAu990 and X Pure Gold. Where the letter X is the manufacturer's code. When jewelry is made of precious metals with different materials or purities, the materials and purities should be indicated separately. When jewelry is too thin or too small to print, it should be accompanied by a logo containing the contents of the imprint. On the eve of the Spring Festival of 20 15, the National Standardization Administration Committee published the revision of GB 1187-2012 "Provisions and Naming Methods of Precious Metals in Jewelry", which took effect on May 4, 2000/6. In the future, even gold with a purity of 999.0‰