18K is not weight, but proportion. Theoretically, the gold content of 100% is 24K.
In fact, gold with a purity of 100% is impossible. Our country stipulates that gold with a purity of over 99.9% is 24K. 18K means that the proportion of gold is 18, 18/24=0.75, that is, 750 thousandths. So 18K gold contains about 75% gold.
The advantage of 18k gold is that its hardness and ductility are better than that of 24K gold, and it is also a precious metal with a gold content as high as 75%. However, the price of 18k gold may be higher than that of pure gold jewelry, because 18k is not 100% pure gold, and because of the process.
Matters needing attention in choosing gold
1, brand: Choose a well-known brand, the quality is guaranteed, but the corresponding brand surcharge has also increased, which will be more expensive. If you can't recognize it, choose famous brands like Lao Fengxiang, Zhou Dasheng and China Gold. Jewelry in regular gold shops will have steel seals, and the format of steel seals is generally: brand+quality+color.
2. Color: Today's gold necklaces are generally made of thousands of gold. The higher the color of thousands of gold, the softer the texture. Therefore, if there is a chain with mosaic, complex pattern or extremely thin chain, the color will be appropriately reduced and changed to pure gold or 18K. However, the reduction of color will not reduce the unit price, but the processing cost will be higher.
3. Weight: The weight of gold jewelry is calculated in grams. Generally speaking, the length of the gold necklace worn by girls is about 45cm. The gold necklace worn by boys is about 50cm long.
4. Price: The price of gold will be affected by factors such as international gold price and exchange rate. So pay attention to whether the price is reasonable when buying.
The above contents refer to Baidu Encyclopedia-18K Baidu Encyclopedia-Gold.