Gold, also known as gold, chemical element symbol for Au, is a metal with a yellow luster. Gold has good physical properties, stable chemical properties, a high degree of ductility and the number of rare and other characteristics, not only for reserves and investment in special currency, but also the jewelry industry, electronics, modern communications, aerospace and aviation industry and other sectors of the important materials. Before the 1970s, it was the world's currency, and still occupies a place in the international reserves of various countries, and is a special commodity with monetary properties, commodity properties and financial properties at the same time.
The categories of gold
1, cooked gold: is raw gold after smelting, purification of gold, generally higher purity, finer density. According to the color of the high and low cooked gold is divided into pure gold, red gold, color gold 3 kinds
2, pure gold: more than 99.6% color
3, full gold - gold content is not less than 990 ‰
4, full gold - gold content is greater than 999 ‰.
5, red gold: and the meaning of pure gold is close to different locations, different standards, the international market for the sale of gold, color up to 99.6%
6, for red gold. And the territory of the red gold is generally between 99.2% -99.6%, usually more than 99%.
7, color gold is gold containing silver, steel and other metal impurities. Because of its color is very complex, according to the impurities it contains different, and can be divided into clear color gold and mixed color gold two kinds.?
①Clear gold (only silver)
Gold contains only silver components, known as clear gold. Its color in about 95%, reddish yellow; 80% of the positive yellow; 70% of the greenish yellow, commonly known as "seven green, eight yellow, nine five red".
② mixed-color gold (small mixed gold, large mixed gold)
Gold contains silver, but also contains steel, zinc, tin, aluminum and other metals, are called mixed-color gold.
8, mixed-color gold according to its copper content, and is divided into small mixed gold and large mixed gold.
Small mixed gold: the total amount of impurities contained in gold, containing copper is not more than one-tenth, known as the small mixed gold (such as 95% color gold, containing 5% of the quality of impurities, the amount of copper is not more than 0.5%). Its characteristics: the color is slightly redder than the clear gold, the body is harder. Jinbao, gold bars on the surface of the hemp islet dots, not glossy, the center is not whole, hit the slightly long rhyme.
Large mixed gold: gold contained in the total amount of impurities, containing more than one-tenth of copper, known as the large mixed gold (such as 90% color gold, impurity content of 10%, copper content of more than 1%). Its characteristics: red copper big mixed gold, its skin slightly show purplish red, after the fire, that is, become black, color in 90% below, cut the ballast mouth is shell crystal sand ballast, body hard and brittle, hit with long rhyme, bronze big mixed gold, skin wrinkled not light and moist, body light, hit with copper sound, grinding road when the hair slippery.
K gold
Silver, copper according to a certain proportion, according to the formula of 24k gold for the preparation of gold. k gold containing silver proportion, the more the more the color of the green; containing copper proportion is large, then the color is purple-red. China's k gold in the early liberation is calculated according to the standard of 4.15% per k. After 1982, has been harmonized with international standards to 4.1666% per k as the standard.
Using "k gold" to indicate the purity of gold
Each k contains 4.166666% of gold
9k=100/24*9=37.5% (375‰)
14k=100/24*14=58.333% (58.5%)
18k=100/24*18=75% (75%)
18k=100/24*18=75% (75%)
This is the first time that gold has been used as a standard in the early days of liberation. (75%)
22k=100/24*22=91.666666% (91.6%)
24k content of 99.6% or more (including 99.6%)
(These kinds of K gold content for the general specification of jewelry, the state regulations lower than 9K gold jewelry can not be called gold jewelry.)
Slogan of Fineness of The Gold Content
1, different color of gold, its color and luster are different, color mnemonic "seven green, eight yellow, nine with red (or nine mouth red), four or six does not show gold.
2, seven green: refers to seventy percent (containing 70% gold) of the color of gold presented by the greenish-yellow.
3, eight yellow: refers to eighty percent (80% gold) of the color of gold is positive yellow.
4, nine with red: refers to 90% (90% gold) of the color of gold presented by the red gold.
5, four or six does not present gold: refers to the color of less than 60% (60% gold) of the gold, its color is not the color of gold
6, 60% of the gold below the white with a slight yellow, 40% of the gold below the color of the gold, the color of the whitish.