K gold refers to the alloy in which gold and other metals are mixed together. Because its English is Karat Gold, it is called k gold for short. Kai is the unit of measurement of K gold. Pure gold is divided into 24 parts, which are divided into different K gold according to the gold content in jewelry, so 24K refers to pure gold, and the gold content of 18K is 65438+24 = 75.0%. Because the gold content of 18K is 75.0%, it is also called 750.

Cleaning of gold blackening;

If there is a black silver film on the surface of gold jewelry, the cleaning method can be mixed with 2 grams of salt, 7 grams of baking soda, 8 grams of bleaching powder and water to form a gold cleaning agent. After soaking the gold jewelry for one hour, rinse it with water and then gently wipe it with a soft cloth.

Although there are some ways to clean with toothpaste, many toothpastes are granular now. From the basic knowledge of gold, we know that gold is soft and easy to scratch, so it is not suitable for toothpaste cleaning. The most correct way to clean gold is to take it to a jewelry store for professional cleaning.