According to its nature, gold can be divided into "raw gold" and "ripe gold". Raw gold, also known as "primary gold", "natural gold" or "barren gold", is unrefined gold mined from mines or river beds. All refined gold is called "cooked gold".
When other elements are added to cooked gold, the color of gold will change. People usually refer to the ripe gold containing only silver and no other metals as "pure gold" and the gold containing silver and other metals as "mixed gold".
K-gold is the expression of color quality of mixed color gold, 4. 1666% gold is lK, and gold can be expressed as 24K, 22K, 20K, 18K according to the color quality of K-gold. The gold content of 24K gold is 99.998%, which is basically pure gold, and the gold content of 22K gold is 9 1.665%.
The fineness of gold can also be directly expressed by content percentage, usually expressed by dividing the weight of gold by 65,438+0,000 parts. For example, 99.99% marked 9999 and 58.6% marked 586.
Signs on gold jewelry
Gold is a popular precious metal, which has been used as currency and jewelry for centuries. Egyptians believe that they are the first beneficiaries who know how to make works of art with gold and how to separate gold from other metals and impurities with clay utensils.
In China, as early as 4,000 years ago in the Yu Xia era, China people already knew how to use gold and silver as decorations and commodities. During the Spring and Autumn Period and the Warring States Period, gold and silver have been widely used as decorations by court nobles and are symbols of wealth. Nowadays, in addition to using gold to preserve the value, the innovation of process design also makes the public pay more attention to the style of gold ornaments.
Gold purity rule
Laws of Hong Kong:
Thousands of pure gold: Jewelry with a gold content of 999.9 per thousand will be engraved with the words "Thousands of pure gold" or "Au999.9".
Pure gold: the gold content is not less than 999%, and the words "pure gold" or "Au999" will be engraved on the jewelry.
Domestic law:
Thousands of pure gold: the gold content is not less than 999%, and the words "thousands of pure gold" or "Au999" are engraved.
Pure gold: the gold content is not less than 990%, and the words "pure gold" or "Au990" are engraved.