In ordinary people’s perception, gold jewelry is equal to gold. In fact, there are many jewelry with gold characters, but the difference is quite big, such as pure gold, K gold, gold-filled, gold-plated, etc. Different types of gold jewelry have different fineness, purity and color. More expensive jewelry such as pure gold and K gold are often counterfeited. How to identify and distinguish these gold jewelry?
Today we will learn about the differences between pure gold, k gold, gold-filled and gold-plated jewelry and the easy-to-learn identification methods.
1. Pure gold
Pure gold jewelry is golden yellow, with a bright but soft luster, a hardness of 2.5, a density of 19.32g/cm3, a melting point of 1064 degrees Celsius, and good ductility. One gram of pure gold can be drawn into a 2,500-meter-long filament. Hammered into 9.6 square meters of gold foil, this shows the good ductility of gold.
According to the current national standards, gold with a purity exceeding 990 can be called pure gold. So how to identify pure gold?
Four steps to identify pure gold
According to international regulations, all precious metals must be stamped with a steel seal somewhere on the jewelry during production. The information contained on the steel seal includes the gold content and the manufacturer. According to regulations, anything with a gold content greater than 990 is now pure gold.
The density of gold is 19.32g/cm3, which is more than twice the density of copper. When we weigh gold with our hands, we will feel like it is falling, but copper does not have this feeling.
3) Listen to the sound
If gold jewelry falls freely onto the concrete floor, there will be a muffled sound, while its imitations will make a crisp sound. In addition, pure gold jewelry has small elasticity and will generally not bounce up when dropped to the ground, while its imitations will make a snapping sound. Because of the good elasticity, most of them will bounce a few more times.
Pure gold is relatively soft, with a hardness of only 2.5, which is about the same hardness as human fingernails, so nails can generally make marks on pure gold. (Of course, although this is a method, the appearance of the mark may be affected, so it is not recommended to use this method to test unless it is absolutely necessary).
2. Yellow Series K Gold Jewelry
K gold (or karat gold) is an alloy formed by fusing gold with other metals. The “K” of K gold is the foreign word “Karat”. The complete representation is: Karat gold (i.e. K gold). “AU” or “G” is the symbol used internationally to indicate the purity of gold (i.e. gold content). .
The yellow series of K gold jewelry is an alloy of gold, silver, and copper. Depending on the gold content, K gold series jewelry with different K numbers can be made, specifically 24K gold, 22K gold, 18K gold, 9K gold, etc.
The depth of color of yellow K gold series jewelry is related to the gold content and the proportion of silver and copper in K gold. The color of 18K gold jewelry is yellower than that of 14K and 10K gold jewelry. For gold jewelry with the same K number, if the silver is more yellow than copper, it will be lighter, and if the copper is more yellow than silver, it will be darker.
K gold identification method:
The easiest way to identify K gold jewelry is to observe the mark. Generally, European and American manufacturers put a numerical mark on the back of K gold jewelry, such as 750, 585, 375 and the factory mark, while China and Hong Kong mostly print K number, such as 22K, 18K, 14K and factory mark. In addition, the hardness of K gold jewelry is above 3.5, the surface is hard and smooth, and it cannot be scratched with a copper needle.
3. White series of K gold jewelry
The gold jewelry of the white K gold series is white with a slight bluish-yellow color, and is marked with the WG mark. It can be divided into the following two types according to the combination:
The first alloy that is mainly composed of gold and a combination of silver, nickel, and zinc is called K platinum in the business world. 18K white gold is composed of 75% gold and 25% silver, nickel, and zinc. 14K white gold is an alloy composed of 58.5% gold and 41.5% silver, nickel, and zinc.
The second type is an alloy composed mainly of gold and palladium, plus copper, nickel, and zinc. The proportion of each metal in K platinum is used as the basis for the title internationally. Currently, there are only two varieties. That is, 334K platinum and 266K platinum. 334K platinum is K platinum composed of 3 parts gold, 3 parts palladium and 4 parts copper, nickel and zinc. Some people also call it 60% K platinum. 226K white gold is K platinum composed of 2 parts gold, 2 parts palladium and 6 parts copper, nickel and zinc. It is also called 40% K platinum. Some manufacturers in Hong Kong believe that the price of 334K platinum and 18K gold, and the price of 22K platinum and 14K are the same. They also call them 18K gold or 14K gold, and mark them as 18K gold and 14K gold.
K platinum identification method:
The way to identify K platinum is to look at the mark. The color of K platinum is white with a slight bluish-yellow color. The luster is not as bright as platinum, and it is a bit black. The hardness is 3.5, which is not as hard as platinum (hardness is 4.3). The density is also lower than platinum.
4. Red Series K Gold Jewelry
The red series K gold jewelry is an alloy mainly made of gold and copper, with a small amount of silver added, and is light red in color. It is a favorite type of K gold jewelry among Europeans, and Russians especially prefer red 14K gold jewelry.
Red K Gold identification method:
The identification method is the same as the yellow series K gold jewelry except that the color is red. The gold content and factory mark are also marked on the inside of the jewelry.
5. Gold plated jewelry
Many gold-plated jewelry are mainly made of copper. A layer of gold is plated on the surface of the copper through electroplating. However, the electroplating layer of gold is very thin, so there is still a difference between such gold-plated jewelry if you look closely. Although the luster is bright , soft, but not durable. If worn for a period of time, the gold-plated layer will be worn away, and the brass body will be exposed, resulting in a dull and different red-yellow color, and the color of the worn gold-plated areas will remain. It will turn black.
Gold plating identification method
(1) Carefully observe whether there are gold-plated areas at the joints or recessed corners of the jewelry;
(2) In addition, its density is small, it is relatively light when weighed by hand, and it has no falling feel. It makes a crisp “beep” sound when it hangs on the ground, and it has good elasticity and will jump;
(3) Generally there is no mark, but sometimes the GP logo is printed.
6. Gold filled jewelry
Gold-filled jewelry is actually relatively easy to understand. Copper products or silver jewelry are wrapped with a layer of pure gold foil, and then processed into various jewelry.
Don’t think that gold foil is very valuable. In fact, gold foil is very cheap, because one gram of pure gold can be hammered into 9.6 square meters of gold foil. Gold-covered jewelry generally laminated very well, and gold foil will not Open easily.
7. Wrapped gold jewelry
The metal composition of any part of pure gold jewelry and K gold jewelry is the same, while wrapped gold jewelry is two or more metals attached or forged together, wrapped around each other, and the metal composition is different in different parts. Its surface is all gold, while its interior is copper and silver.
8. Gilt jewelry
Gilding is an ancient gold plating process. It is to evenly coat a layer of gold and mercury mixed slurry on copper, silver and other low-value jewelry, and then bake it at a low temperature. The mercury evaporates when heated, and the gold The surface of the copper is attached, then flattened and polished. Currently, this method is rarely used. Because there is a very thin layer of gold on the surface of wrapped gold jewelry, it is somewhat deceptive, but it still retains the characteristics of copper products, such as low density.
Gilt identification method
Weigh it gently with your hands and it will beat continuously after falling to the ground. Generally, there are no marks. You should pay attention to identify it when purchasing.