What Are 24K Gold and 18K Gold? What's the Difference?
Let's start with the concept of K gold. K gold is an alloy formed by melting gold together with other metals. K (Karat) is the unit of measurement for gold content. The calculation method for K gold is to divide pure gold into 24 parts. 18K gold is an alloy with a gold content of 18/24, with the remaining 25% being other precious metals, including platinum, nickel, silver, palladium, and so on.
24K Gold
24K gold generally refers to pure gold in common usage. A gold content of 99.99% or above can be called 24K. 24K gold has the highest value and the best value retention. Although it can be made into various kinds of jewelry, it is relatively soft and easily deformed, so it is mostly used for processing pure gold necklaces, rings, and so on, and is not suitable for additional gemstone setting. Many people buy 24K gold jewelry mainly for value preservation and storage, and fewer people wear it.
18K Gold
An 18K piece of jewelry refers to one in which the pure gold content is 18/24, that is, it is composed of 75% gold plus 25% other metal alloys. Therefore, 18K gold is also called AU750. 18K gold jewelry not only possesses the precious value of gold, but also, because of its perfect composition ratio, has a higher hardness than pure gold. It has the advantages of strong ductility and the ability to be adjusted into various colors (18K yellow gold, white gold, rose gold). When used in jewelry design, it allows complex and exquisite creative expressions to be fully realized, and it is suitable for making jewelry of all kinds of styles. Most jewelry on the market, such as diamonds, gemstones, and jadeite, uses 18K gold for setting these expensive jewels.
In fact, 18K gold is more suitable than pure gold for creation, because the Mohs hardness of gold is 2.5, and its soft texture is not conducive to jewelry setting, shaping, and so on. But 18K gold is different. By incorporating other metals such as copper and silver, it can enhance the toughness of gold, precisely making up for this shortcoming. Furthermore, 18K gold is also the gold content ratio favored by high-end jewelry makers, because a proportion of 75% has already reached a high gold content, while the other 25% can use other metals to enhance craftsmanship, achieving a balance between precious material and refined craftsmanship.
The hallmark on 18K gold jewelry is often marked Au750, 750, or 18K, which indicates that the gold content is 75%.
18K White Gold
18K white gold is a white alloy made by melting gold with metals such as palladium or nickel, silver, copper, and zinc. Its main component is still gold. Because white K gold appears white, it is the white metal most easily confused with platinum, but it is actually a completely different metal from platinum. To be precise, 18K white gold should be called 18K white K gold. It is a white K gold formed by melting 75% gold with 25% palladium or nickel, silver, copper, and other metals. Its main component is still gold, so it should not be confused with platinum, which is naturally white.
18K Rose Gold
The composition of rose gold is: pure gold, copper, silver/zinc.
The following are the gold contents of various types of K gold:
24K gold – gold content >= 99.9%
18K gold – gold content >= 75%
14K gold – gold content >= 58.5%
24K gold is relatively soft. If you accidentally knock it against something, it can deform quite easily.
