1. Red gold and pure gold have similar meanings, but the standard of red gold varies with time and place. Gold with a purity of 99.6% sold in the international market is called red gold. Domestic red gold is generally between 99.2% and 99.6%.
2. Non-ferrous gold, also known as "secondary gold" and "tidal gold", refers to gold with low fineness. Due to the different contents of other metals, the purity of these gold is as high as 99% and as low as 30%.
According to the classification of other metals, ripe gold can be divided into solid gold, mixed gold and K gold. Clear gold means that gold is only mixed with silver, regardless of its fineness. Clear gold is more common in gold bars, ingots, nuggets and various utensils and gold ornaments.
3. Mixed color gold means that besides silver, gold also contains other metals such as copper, zinc, lead and iron. According to the different types and quantities of metals, it can be divided into small mixed gold, large mixed gold, bronze mixed gold and lead mixed gold.
4. K gold means that silver and copper are mixed in a certain proportion, and the pure gold calculated according to the formula is 24k. Generally speaking, the more silver in K gold, the bluer the color; If the proportion of copper is large, the color is purple.
The percentage represented by the value of k is only an approximation, and it is not required to be very accurate. Traditionally, even k values are used, such as 24K, 22K, 20K, 18K, etc. 18K means that 24 parts of alloy contain 18 parts of gold, which is equivalent to about 75%. Calculation method of K gold: You can say that the calculation formula of converted gold content of K gold is: K value ÷24× 100% (that is, K value × 4. 1667%).
Extended data:
Methods for judging the fineness and purity of gold;
1. Use "k gold" to indicate the purity of gold.
According to the national standard GB 1 1887-89, the gold content of each opening (abbreviation for carat in English, karat in German, often written as "K") is 4. 166%. Therefore, the gold content of each opening is (GB in brackets):
8k=8*4. 166%=33.328%(333‰)
9k=9*4. 166%=37.494%(375‰)
10k = 10 * 4. 166% = 4 1.660%(4 17‰)
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‰)
2 1k = 2 1 * 4. 166% = 87.486%(875‰)
22k = 22 * 4. 166% = 9 1.652%(9 16‰)
24k = 24 * 4. 166% = 99.984%(999‰)
24k gold is often regarded as pure gold, which is "1000‰", but the actual gold content is 99.99%, which is converted into 23.988k.
2. Use language to express the purity of gold
Some gold ornaments are marked with words, and their provisions are as follows:
Pure gold-the gold content is not less than 990‰
Thousands of pure gold-the gold content is not less than 999‰
Others are directly marked with the actual gold content.
3. Use fractions to express the purity of gold.
If marked as 18/24, the color is 18k(750‰).
If marked as 22/24, the color is 22k(9 16‰).
4. Use Arabic numerals to indicate the purity of gold.
For example, 99- means "pure gold"
For example, 999 means "thousands of gold"
In China, there are regulations on the imprint and identification card of gold products, which generally require the manufacturer's code, material name, content imprint and so on. No mark, the product is unqualified. The same is true internationally. But for some very small products, it is also allowed to be unmarked.
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