AU750 refers to an alloy containing 75% gold and 25% other metals, commonly known as 18K gold. Stamped AU750 is usually used by jewelry manufacturers or gold processors when making jewelry or gold ornaments to indicate its material composition.

In China, there are relevant laws and regulations on the imprint, logo and quality certificate of gold products to ensure the rights and interests of consumers and fair competition in the market. Therefore, under normal circumstances, only legitimate jewelry manufacturers or gold processors are qualified to engrave seals such as AU750 on their products.