18K gold is an alloy containing 75% gold and 25% other metals, which are melted together. Because 25% of other metals have different compositions, they can be smelted into 18K gold with different colors. At present, there are three common colors on the market: 18k platinum, 18k gold and 18k rose gold. First of all, the hardness of 18K gold is higher than that of platinum, so it can be made into relatively complicated styles.

18k gold also has strong ductility, so it can be used to create varied styles and even some complicated details, which is incomparable to other metals.

18K gold can maintain stable performance in various extreme environments and is not easy to wear and deform. At the same time, it can also give the strongest protection to gems and be competent for flexible, complex and fashionable styles.

In fact, the discoloration of 18k gold products is not the discoloration or fading of 18k gold. As mentioned above, 18k gold refers to gold ornaments with a gold content of 75%, and the other 25% is other precious metals. The color of metal mainly depends on the proportion of 25% other metals. For the beauty and durability of jewelry, a coating is usually electroplated on the outer surface of jewelry.

As we all know, 99% of human sweat is water, and about 1% is waste and harmful substances in human body, such as chlorinated substances, lactic acid, urea, ammonia and so on.

When these substances come into contact with silver and copper in 18k gold, they will react chemically to produce silver chloride and copper sulfide, and present dark black chemical salts, destroying the coating on the surface of 18k gold, thus causing the "discoloration" of 18k gold.