When we want to buy gold, we must reserve some knowledge about gold in advance, such as how to distinguish the purity of gold, so that we can spend less money to buy the purest gold. The following describes the determination method of fineness and purity of gold:
1. Use K gold to express the purity of gold
According to the national standard gb11887-89, the gold content of each carat (abbreviation of English carat and German karat, often written as K) is 4.166%. Therefore, the gold content of each carat is respectively (national standard in parentheses):
8k=8*4.166%=33.328%(333‰)
9k=9*4.166%=37.494%(375‰)
10k=10*4.166%=41.660%(417‰)
12k=12*4.166%=49.992%(500‰)
14k=14*4.166%=58.324%(583‰)
18k=18*4.166%=74.998%(750‰)
20k=20*4.166%=83.320%(833‰)
21k=21*4.166%=87.486%(875‰)
22k=22*4.166%=91.652%(916‰)
24k=24*4.166%=99.984%(999‰)
24K gold is often considered pure gold and becomes 1000 & permil, However, the actual gold content is 99.99%, which is converted into 23.988k.
2. Express the purity of gold in words
Some gold jewelry is marked with text, which is as follows:
Full gold -- the gold content shall not be less than 990 & permil;
Thousand gold -- the gold content shall not be less than 999 & permil;
Some are directly marked with the actual gold content.
3. The purity of gold is expressed in fractions
If it is marked as 18 / 24, the color is 18K (750 & permil;)
If it is marked as 22 / 24, the color is 22K (916 & permil;)
4. Use Arabic numerals to indicate the purity of gold
For example, 99 means full gold
For example, 999 -- means thousands of gold
China has regulations on the marks and signboards of gold products. Generally, it is required to have the manufacturer code, material name, content mark, etc. if there is no mark, it is a nonconforming product. The same is true internationally. However, it is also allowed not to mark some particularly small products.