The name of gold depends on the purity of gold, and 925 gold refers to gold with a purity of 92.5%. Gold with a purity of 99% is called pure gold, gold with a purity of 99.9% is called thousand gold, and gold with a purity of 99.99% is called thousand gold, which can also be called one hundred thousand gold or high pure gold.
According to the "Regulations and naming Methods for the purity of Precious Metals in Jewelry" (national standard GB/ T11887-2002), the minimum value of the thousand fraction of pure gold is 990, that is, the purity is not less than 990‰; The minimum value of the thousand fraction of pure gold is 999, that is, the purity is not less than 999‰.
In the standard here, the purity range of the precious metal in the precious metal jewelry does not include the solder composition, but the finished product content must not be lower than the specified purity range. The national standard on the purity of gold refers to the minimum value of purity, and the purity of most of the gold and gold raw materials in the domestic market exceeds this minimum value (the purity of gold reached 995‰, the purity of gold reached 999.5‰).
The higher the purity of gold jewelry, the darker the color. In the absence of a gold medal, the general color can be determined according to the following color (with lapis gold as the criterion, the so-called lapis gold contains only silver components). Deep red yellow color is more than 95%, light red yellow 90-95%, light yellow 80-85%, green yellow 65-70%, green with white light only 50-60%, light yellow and white is less than 50%