Is sf38 Pure Gold 999 written on the inside of the gold ring pure gold?

999 is pure gold error correction: if it is written as pure gold 999, there is a problem.

National standard GB11887-2012 (jewelry? Provisions on purity and naming method of precious metals):

Pure gold is 990% gold, and 999 is pure gold. Such a standard method is contradictory to both.

Theoretically, 999 is pure gold 24k, but the extraction purity of precious metals in the existing industry can not meet such high requirements.

SF38 is the factory serial number. Each manufacturer's jewelry company is represented by a different numerical code.