Types of gold
1. Cooked gold: It is gold refined from raw gold, generally with high purity and fine density. According to the fineness, ripe gold is divided into pure gold, red gold and colored gold.
2. Pure gold: the purity is over 99.6%.
3, pure gold, the gold content is not less than 990‰.
4. Pure gold-the gold content is greater than 999‰.
5. Red gold: similar to pure gold, the standards vary from place to place. The purity of gold sold in the international market is 99.6%.
6. It is red gold. Domestic red gold is generally between 99.2% and 99.6%, generally above 99%.
7. Colored gold refers to gold containing other metal impurities such as silver and steel. Because of its complex color, it can be divided into clear gold and mixed color gold according to the different impurities contained. ?
① Pure gold (silver only)
Gold contains only silver and is called pure gold. Its fineness is about 95%, which is red and yellow; About 80% is yellow; About 70% is bluish yellow, commonly known as "seven greens, eight yellows and nine five reds".
② Mixed color gold (small mixed gold, large mixed gold)
Besides silver, gold also contains other metals such as steel, zinc, tin and aluminum, which are collectively called mixed color gold.
8. Variegated gold can be divided into small variegated gold and large variegated gold according to its copper content.
Small mixed gold: Gold with impurity content less than one tenth of the total impurity is called small mixed gold (such as 95% gold with purity of 5% and copper content less than 0.5%). Its characteristics: the color is clear, the gold is reddish, and the body is hard. There are small spots on the surface of Jinbao and gold bars, which are not smooth, the center is incomplete and the impact is slightly longer.
Large mixed gold: Gold with an impurity content exceeding one tenth of the total impurities is called large mixed gold (for example, gold with a purity of 90% has an impurity content of 10% and copper content exceeding 1%). It is characterized by red copper mixed with gold, and the skin is slightly purple. It turns black after burning, and the fineness is below 90%. The slag cutter is shell crystal sand, which is hard and brittle. Strike it with a long rhyme, bronze mixed with gold. The skin wrinkles are not smooth, and the body is light and floating. There is a copper sound when knocking, and it is slippery when polishing.
K gold
Refers to the gold prepared by silver and copper in a certain proportion according to the formula that pure gold is 24k. The more silver in K gold, the bluer the color. If the proportion of copper is large, the color is purple. China's K-gold was calculated at the standard of 4.15% in the early days of liberation. After 1982, it has been unified with international standards, with the standard of1666% per k4.
The purity of gold is expressed by "K gold".
The gold content per k is 4. 166666%.
9k= 100/24*9=37.5% (375‰)
14k = 100/24 * 14 = 58.333%(58.5%)
18k = 100/24 * 18 = 75%(75%)
22k = 100/24 * 22 = 9 1.66666%(9 1.6%)
The content of 24k is above 99.6% (including 99.6%).
(These kinds of K gold contents are general specifications of jewelry, and the state stipulates that gold jewelry below 9K cannot be called gold jewelry. )
The slogan of gold content and fineness
1. Gold with different fineness has different colors and luster. The formula of fineness is "seven greens, eight yellows, nine reds (or nine reds), and four or six are not gold".
2. Seven colors: it means that 70% (including 70% gold) of gold is bluish yellow.
3. Eight yellows: It means that 80% (including 80% gold) of gold is yellow.
4. Nine with red: It means that 90% (including 90% gold) of gold is red gold.
5. 46 does not show gold: refers to gold with a purity of less than 60% (including 60% gold), and its color is no longer the color of gold.
6. Less than 60% of gold is yellowish white, and less than 40% of gold is completely white.