Can you tell the authenticity of gold by looking at the marks on gold jewelry? I wonder what the mark on the jewelry is for.
What is invisible to the mark can only be determined by color and weight.
The above marks only indicate the gold content of gold, generally 9999 and 9997, depending on the gold content. The smaller the gold content, the smaller the gold content. Some are alloy, and only four nines can be called thousands of gold.