Au750 is commonly known as 18K gold. Usually used to make jewelry, the imprint is G 18K, G750 or Au750 "where G represents gold content".
"18K" (or au750) jewelry refers to a kind of jewelry with pure gold content of 18, that is, 75% gold plus 25% other metal alloys (such as silver, palladium, zinc, nickel, etc. ).
18K gold ornament not only has the precious value of gold, but also has the advantages of strong ductility, high hardness and changeable colors due to its perfect composition ratio.
The gold content of 18K gold is the general specification of jewelry, and the state stipulates that gold jewelry below 9K cannot be called gold jewelry. Some gold ornaments are marked with words, which stipulate that pure gold-the gold content is not less than 99%, and thousands of gold-the gold content is more than 99.9%.
In China, the imprint and identification card of gold products are stipulated. Generally, it is the manufacturer's code, material name, content stamp, etc. They are all necessary, and products without marks are unqualified. The same is true internationally. But for some very small products, it is also allowed to be unmarked. The gold seal of 18K is generally AU750, 18K or G750.
Extended data:
The fineness of Au750 gold can be determined according to its other 25% gold-bearing species.
The main epidemic types in China are divided into:
Platinum: 75%+ silver, nickel+zinc (nickel shall not exceed 0.3%).
Platinum: 75%+ silver+chromium
Blue gold: 75%+ iron (appropriate)
Black gold: iron over 75% thick.
Zijin: Lead content exceeds 75%
Gold: 75%+ Nickel+Silver+Zinc
Rose gold: 75%+ copper+silver+zinc
Platinum: 75%+ silver+nickel+platinum+zinc or 75%+ palladium, slightly bluish white.
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Baidu encyclopedia _Au750