The numerical designation of gold represents its purity. 999 means thousand pure gold, and the purity of gold is nine hundred and ninety-nine thousandths; 9999 means ten thousand pure gold, which means the purity of gold is nine thousandth thousandths. Nine hundred and ninety, a difference of nine ten thousandths. \x0d\\x0d\ \x0d\ The main difference between gold 999 and 9999 is the purity. 999 has a gold content of 99.9, and 9999 has a gold content of 99.99. But when making jewelry, because it requires welding, 99.9 is the highest. When it comes to jewelry, 9999 That's just deceiving people. Gold bars are usually 9999. \x0d\\x0d\ In fact, there is basically no difference between the prices of 999 and 9999. Generally, the raw materials of big brand jewelry are 9999 gold nuggets, and the jewelry made can only be 999 pure gold or pure gold.