What is the difference between 9999 gold and 999.9 gold?

Do you know the difference between gold 999 and gold 9999? They don't just have different names. Gold 999 is pure gold with a gold content of not less than 99.90%, and gold 9999 is pure gold with a gold content of not less than 99.99%. In addition to different purity, they also have the following differences: 1, different hardness. There is a great difference in hardness between gold 999 and 9999. If you scratch the surface of gold with a hard object, gold 999 will leave a very shallow trace, while the trace left on gold 9999 will be very obvious. 2. The price of gold 999 is lower than that of gold 9999. Gold 999 is generally used as the material of gold jewelry, while gold 9999 is mostly used as the material of gold bars. 3. Gold 999 for different purposes is usually used to make jewelry, while gold 9999 is usually used as a raw material for jewelry or circulated in the market. Therefore, if it is only worn for buying gold jewelry, there is no need to demand the purity of 99.99 million gold. 4. Different colors are very different. Because the purity of gold 999 is low, it is mainly golden yellow, while the purity of gold 9999 is high, it will be dark yellow.