Pure gold jewelry is golden yellow, bright and soft, with a hardness of 2.5, a density of 19.32g/cm3, a melting point of 1064 degrees Celsius with good ductility, and one gram of pure gold can be drawn into a filament of 2,500 meters, be hammered to 9.6 square meters of gold foil, which shows the good ductility of gold. As far as the current national standards are concerned, if the purity of gold exceeds 990, it can be called pure gold. How to identify pure gold?
All precious metal get name necklace jewelry according to international regulations must be marked on the inside of the jewelry. The imprint requires marking the imprint content and the manufacturer. Any gold content greater than 990 can be called a full gold.
The density of gold is 19.32g/cm3, which is more than twice the density of copper. The handcuffs of gold have the feeling of falling hands and the handcuffs of copper are heavy but not have the feeling of falling hands.
Free fall of gold jewelry on the concrete floor will make you squeak, and its imitation is the crisp sound of the cockroach. In addition, the pure gold jewellery has a small elasticity, and it will not bounce off when it falls to the ground, and its imitation most of them will bounce a few times because of the good elasticity.
The hardness of the gold jewelry is 2.5 and the hardness of the human nail is equivalent, so the nail can be used to draw fine marks.
Yellow series of K gold jewelry
The yellow series of K gold jewellery is an alloy of gold and silver and copper. The gold content can be made into K gold series jewellery with different K numbers. There are mainly K jewellery with 22K, 18K and 14K, Asians who like high K number. Such as 22K and 18K. Europeans and Americans like 14K gold and 10K gold jewelry. The color of the yellow K gold jewelry is related to the content of gold in K gold and the ratio of silver to copper. The color of 18K gold jewelry is yellower than the gold jewelry of 14K and 10K. The gold jewelry of the same K number, if the silver more than copper, yellow will be lighter. On the contrary, yellow will be deeper.
White series of K gold jewelry
The gold jewellery in the white K gold series is white with a bluish yellow color. The imprints are marked with a WG mark. The combination can be divided into the following two types.
The first alloy, which is dominated by gold and combined with silver, nickel and zinc, is called K Platinum in the business world. 18 K’s K Platinum is a combination of 75% gold and 25 % silver, nickel, and zinc. 14 K’s K Platinum is an alloy of 58.5 % gold and 41.5% silver, nickel and zinc.
The second type of alloys consisting of gold and copper, combined with copper, nickel and zinc, is based internationally on the basis of the share of each metal in K Platinum. Currently there are only two varieties. That is 334K Platinum and 266K Platinum 334K Platinum is K Platinum composed of 3 parts of gold, 3 parts of gold and 4 parts of copper, nickel and zinc. Some people also call it 60% Platinum. 226K Platinum is 2 parts of gold, 2 parts of gold and 6 parts of copper, nickel and zinc, also known as 40% Platinum. Some manufacturers in Hong Kong believe that the price of 334 K Platinum and 18 K gold, the price of 22K white gold and 14K are the same, and it is also called 18K gold or 14K gold, and is marked with 18K gold and 14K gold. In addition to looking at the imprint, K Platinum has a slightly greenish white color. The gloss is not as bright as platinum, and some are black; the hardness is 3.5, there is not harder than platinum (hardness is 4.3), and the density is lower than that of platinum.
Red series of K gold jewelry
The red series K gold jewellery is made of gold and copper, with a small amount of silver alloy, and the color is reddish. It is a favorite K gold jewelry of Europeans, and Russians especially prefer red 14K gold jewelry. In addition to the red color, the other methods are the same as the yellow series K gold jewelry. The inner side of the jewelry is also marked with the gold content mark and the factory record.
Wrapped gold jewelry
The composition of the metal in any part of pure gold jewellery and K gold jewellery is the same, while the wrapped gold jewellery is two or more kinds of metal attached or forged together, wrapped in each other, and the metal composition is different in different parts. Its surface is gold, and the interior is copper and silver.
Gold-plated jewellery is made of copper on the surface of the jewellery. It is plated with a layer of yellow gold, but the coating is generally thin, around 3 to 5 mm. This gold-plated jewellery is bright, soft, but not durable, as easy to wear as a gold-plated strap, revealing a brass tire with a dim yellow color. This kind of gold-plated jewellery is easier to identify. Look carefully at the joints of the jewellery or the corners of the corners. There will be no gold plating. In addition, its density is small, the weight is light, no falling hand feeling. When it falls on the ground, there is a crisp “beat” sound, if the elasticity is good, it will bounce; there is usually no mark, and sometimes the GP mark is printed.
Gild jewellery is a layer of gold foil on a copper or silver plate. The thickness of the gold foil is between 10 and 50mm. Since the thickness of the gold-plated jewellery gold foil is thicker than gold plating, the appearance is similar to that of gold jewelry. This kind of gold-plated jewelry has the mark of K F in the United States. If the gold foil is ISK gold, it will be marked with 18KF on the inside of the jewelry.
Sheet metal jewelry
Sheet metal is an ancient gold-plating process. It is uniformly coated with a thick paste of gold and mercury on low-value jewellery such as copper and silver. Then baked at low temperature, and mercury evaporates when heated. Gold attach the surface of the copper, then flatten and polish it. Currently, this method is rarely used. Because the surface of the wrapped gold jewelry has a very thin layer of gold, it is deceptive, but it still retains the characteristics of copper products, such as the small density of the handcuffs, the continuous bounce after falling, generally no mark, in the purchase should pay attention to identification.