1. Irregular invoice filling: It may be due to the negligence of the drawer or irregular invoice filling, resulting in no information about pure gold.
2. Different brands or specifications of gold may have different naming methods: some brands or specifications of gold may not use "pure gold" as the naming method, so "pure gold" may not be displayed on the invoice.
3. It may be fake gold: some unscrupulous traders may sell fake gold and falsify information on invoices. In this case, there may be no real money information on the invoice.
If you have any questions, I suggest that you can learn more product information from the merchants or contact relevant institutions for testing and certification.