What's the difference between three nines and four nines in gold?

The digital symbol of gold represents its purity, 999 is pure gold, and the purity of gold is 999 per thousand; 9999 is ten thousand gold, which means the purity of gold is 99900/ 10000, which means 9/ 10000. \x0d\\x0d\ \x0d\ The difference between gold 999 and 9999 is mainly the difference in purity. 999 contains 99.9% gold, and 9999 contains 99.99% gold. But if you make jewelry, 99.9% is the highest, because it needs welding. It is a fool to say that jewelry 9999 is a gold bar. \ x0d \ x0d \ In fact, the prices of 999 and 9999 are basically the same. Generally, the raw materials of big brand jewelry are 9999 gold nuggets, and the jewelry made can only be 999 thousand gold or gold.