18k gold is an alloy with a gold content of at least 75%, that is, an alloy with a gold content of 18/24, and the remaining 25% is other precious metals, including platinum, nickel, silver and palladium. 18K gold is a kind of gold ornament with low cost and comfortable wearing. The calculation method of gold is to divide pure gold into 24 parts, and 24K gold is pure gold. However, it is impossible to have 100% gold in reality, so gold with a domestic content of more than 99% and 6% can be called 24k gold. 1, gold jewelry made of gold mainly includes pure gold jewelry and K gold jewelry. Pure gold jewelry is also called pure gold jewelry. There is no shortage of gold, and the purest gold can only reach 99% and 9999%. It is a "reagent gold" specially used as a standard reagent. The content of pure gold jewelry sold by jewelry stores is actually 99% and 99,99%. The former is called "Erjiujin" and the latter is called "Four Seasons Jiujin". K gold is to add a certain proportion of silver, copper, zinc and other metals to gold to increase its strength and toughness. Karatgold's "k" is the abbreviation of "karat". The calculation method of K gold is to divide the pure gold with the highest content into 24K, and the gold content per k is 4 166% (4 15% in the early days of the People's Republic of China, and the common ones are 24K, 22K, 20K, 18K, 12K and 9K).