The classification knowledge of gold jewelry, the matters to be paid attention to when buying
(1) Classification of gold jewelry
1. "Pure gold" jewelry
"Pure gold" is usually divided into full gold and thousands of gold. The color is red, soft and lustrous. But absolute pure gold does not exist. As the saying goes, "gold has no foot." A reagent with a purity of 99.9999%, which is specifically used as a standard chemical reagent, can be extracted at a modern scientific and technological level. Due to the high production cost of reagent gold, it is of little significance to make jewelry with reagent gold only from the use value of jewelry. At present, there are three kinds of gold in the Chinese market: “Four-Nine Goldâ€, the color is 99.99%; “Three-nine Goldâ€, the color is 99.9%, commonly known as the thousand-foot gold; “Two-nine Goldâ€, the color is 99%. Commonly known as full gold.
2. K gold jewelry
K gold is an alloy made by adding some other metals to pure gold to increase hardness, change color tone and lower melting point. Due to the different proportions of other metals added, the properties of K gold, such as color, hue, hardness, ductility and melting point, are different. K gold jewelry is characterized by low gold content, low cost, and can be made into various colors, and is not easy to be deformed and worn, especially after the gemstone is set to be firm and beautiful, and the precious and beautiful gemstone is also displayed. Therefore, it is widely popular in many cities in China. K gold jewelry is rich in color. Currently, there are red K gold, orange K gold, yellow K gold, green K gold, blue K gold, cyan K gold, purple K gold, gray K gold, black K gold, White K gold, white K gold because of its color luster similar to platinum, especially a layer of enamel, is elegant and generous, can be fake, and the price is much lower than platinum, so it is favored by many people. There are three main series of formulas for white gold, namely: gold and palladium, gold and nickel, gold and silver, or an alloy of these combinations, all of which can form white gold.
(2) Simulation of gold jewelry
1. Gold-plated jewelry
Gold-plated jewellery is mostly made of silver or copper. The surface is coated with gold, which replaces the original color of the original material with gold luster, thus enhancing the ornamental value of the jewellery.
The gold-plated gold content shall not be less than 14K and its thickness shall not be less than 0.5 microns. Gold-plated jewellery is generally lighter in weight and harder when bent. In addition, the thin-coated jewels are rubbed hard on the sandpaper to expose the color of the base. After the fire, the color becomes white and the black is copper.
2. Sheet metal jewelry
Sheet metal is a method of making jewelry in ancient times. It dissolves gold in mercury, and then evenly spreads it on the surface of the jewelry. After drying it, it is baked with charcoal fire to volatilize the mercury, and then the agate is used to calender the surface. Become a sheet metal product.
3. Gold jewelry
Gold-plated jewellery is made of silver, copper, lead, zinc and other alloys, and then the gold foil is firmly wrapped on the surface of the metal product substrate by mechanical or other means to obtain a gold coating. The gold content of the gold is not less than 14K, and its thickness is not less than 0.5 microns.
(3) Maintenance of gold jewelry
1. When wearing gold and silver jewelry, avoid contact with hard objects and pull hard. Due to the low hardness of gold and silver, it is easy to be scratched or broken by contact with hard objects, which will destroy the decorative taste of the jewelry.
2. Wear jewelry in areas with chemical contamination. At the same time, try to minimize contact with perfumes, head oil, toilet water and other cosmetics. Once contact, it is easy to cause the surface of the jewelry to corrode and appear spots or discoloration. In order to maintain the luster of gold jewelry, a small amount of detergent can be added to the warm water. Gently brush with a soft brush, rinse with water, then wipe with a soft cloth and dry.
(4) Inspection of gold jewelry
1. Identification
Jewelry imprint should contain the manufacturer code, precious metal material name and content.
2. Appearance Quality
It is mainly the inspection of the specific process quality of the overall shape and processing quality of jewelry.
3. Jewelry weight
Gold jewelry is calculated by weight and processing fee. The weight of the jewelry is one of the important indicators. According to the standard, the unit of measurement of the weight of the jewelry is gram, and the tolerance of the single piece of gold jewelry is 0.01g.
4. Gold content
The gold content in jewelry is an important indicator of its quality. There are many methods for testing gold content, which can be divided into chemical analysis methods and instrumental analysis methods. According to whether the jewelry is damaged during the testing process, it can be divided into non-destructive testing method and lossy testing method. The daily inspection in the jewelry quality supervision department is generally based on non-destructive testing method. The density method is combined with X-ray fluorescence spectrometry and electron probe. Large instrument analysis. The market supervision and spot check is mainly based on damage detection. The fire test method is the national test method for measuring the gold content in jewelry in China.
(5) Physical properties of gold
Glossy reddish yellow, the color is above 95%; positive yellow, the color is about 80%; blue yellow, about 70%; yellow slightly gray, about 50%.
Density 19.32g/cm3
Hardness Mohs hardness of 2.5, similar to human nails.
--What is Platinum, Platinum, K Platinum and Palladium
In recent years, silver-white precious metal inlaid jewellery has become very popular. In the mall, the names of these precious metals are often overwhelming.
In Taiwan, white gold and K white gold are popularly referred to as white metals (silver is not discussed here). In fact, this kind of statement is often misleading and confusing. We must explain it according to the naming of elements on the chemical periodic table to get a reasonable name.
First, white gold (Whitegold)..
The so-called K Platinum and Platinum in the market is actually an alloy of gold, nickel, copper and zinc. Or gold and silver, or alloys of gold, silver and copper. It also includes alloys of gold and palladium that are often used by Taiwanese masters. Its code name WG (WhiteGold), which means white gold. In the early days, 226 (gold 60%, palladium 2%, copper 2%) was used to represent white gold with pure gold 600/1000, which is commonly known as "material", meaning gold-white metal instead of gold. Nickel alloy (nicklealloy) plating. Generally used in foreign stamps; WG585 (14K), WG750 (18K) or only the number represents gold.
White gold has good reflectivity and is not easy to lose its luster. Before platinum and palladium are used in large quantities in the future, white gold is a silver-white metal mainly used for enamel gemstone jewelry.
Second, platinum (platinum)..
Also known as pure platinum, plus platinum or real platinum. But these names are not reasonable and are easily confused with white gold. Its symbol is Pt, silver gray white, specific gravity 21.35, melting point 1700 ° C, Mohs hardness 4-4.5 degrees, chemically stable, not subject to acid and alkali corrosion except aqua regia.
Pure platinum is relatively soft, and the addition of metals such as ruthenium, osmium, and palladium increases its hardness. South American Indians made platinum jewellery as early as the 15th century. Europeans began to adopt it after the mid-19th century. Japan is currently the largest consumer of platinum.
Third, platinum alloy (platinumalloy)..
Refers to an alloy of platinum mixed with other metals, such as palladium, rhodium, ruthenium, osmium, cobalt, rhodium, copper, and the like. Although platinum hardness is higher than gold, it is not enough as a enamel, and it must be alloyed with other metals to make jewelry.
The jewellery industry uses platinum, rhodium alloys, and platinum and rhodium alloys. Platinum and cobalt alloys are used for casting in Europe and Hong Kong. In Japan, a chain of platinum (85%) and palladium alloy is used. The international platinum stamp is the words Pt, Plat or Platinum, and is represented by the thousandth digit of purity. For example, Pt900 means the purity is 900%. The specifications of Japanese platinum jewelry are marked Pt1000, Pt950, Pt900, Pt850.
Fourth, palladium (.
It is a member of the platinum group, silver white, symbol Pd, specific gravity 12, lighter than platinum, strong ductility, slightly harder than platinum, insoluble in organic acids, cold sulfuric acid or hydrochloric acid. But soluble in nitric acid and aqua regia. Under normal conditions, it is not easy to oxidize and lose luster. At temperatures around 400 °C, oxides are formed on the surface, but when the temperature rises to 900 °C, the gloss is restored. Palladium is currently cheaper than platinum and is used by the jewelry industry alone or as part of gold, silver and platinum alloys. Sometimes some sputum is added to increase its hardness. Gold, palladium K gold and platinum, palladium alloys are common on the market. Specifications are marked with Pd1000, Pd950, Pd900
--The difference between platinum and platinum
1. Thousands of gold refers to pure gold jewelry with a metal content of 99.9%, engraved with 999 or thousands of gold seals.
2. Full gold refers to a pure gold jewelry with a gold content of 99%, engraved with 99% or full gold.
3, 18K gold refers to jewelry containing 75% gold, the remaining 25% is other precious metals, engraved with 18K or 750 imprint.
4, 18K Platinum refers to gold jewelry containing 75% gold, white color, the other 25% is other white yellow metal, engraved with 18K or 750 imprint.
5, Pt900 refers to platinum jewelry containing 90% platinum, the remaining 10% is other precious metals, platinum, palladium content of 950%, imprinted as Pt900.
6. Pt950 refers to jewelry containing 95% platinum, the remaining 5% is other precious metals, imprinted as Pt950.
The metal composition is completely different. On the chemical element list, one is gold and the other is platinum.
How to distinguish between true and false and quality when buying jewelry?
First, view the imprint
National standards stipulate that precious metal jewelry should be marked with origin, manufacturer, materials and content, and unmarked products are unqualified products. If there is a quality problem, the quality inspection agency can give a test judgment based on the imprint. Consumers should purchase the brands they need and the gold ornaments with different gold content according to the imprint.
Second, the sensory test method:
1, look at the color: the foot gold is dark yellow, K gold has yellow, red, white and other multi-color, and the imitation gold products are mostly copper alloy, the color is lighter.
2, 掂 weight: gold weight is 19.3g / cm3 is much higher than the proportion of imitation gold products, such as a gold ring is about 5 grams, and the same size of imitation gold products are generally less than 3 grams.
3, test hardness: pure gold is soft, can be scratched with a pin, bite with a tooth.
Third, if you need to know the content of precious metal jewelry or the quality dispute, you should go to the jewelry quality inspection organization to identify it by physical or chemical analysis.
When buying jewelry, you need to carefully check the inlay, whether the welding is strong, whether it is broken, burrs, trachoma, etc.
Jewelry maintenance: When wearing and storing gold jewelry, avoid contact with articles containing elements such as lead and mercury (mercury), otherwise the surface of the jewelry will be discolored. When working and taking a bath, remove the jewelry to prevent wear or bumps, and do not pull it hard to avoid deformation or breakage.
After wearing the jewelry for a period of time, it may have dirt and dark color. It can be soaked with a washing spirit, gently brushed with a soft brush, rinsed with water, and worn after drying.
Basic knowledge of platinum (platinum) jewelry
Platinum is also known as platinum, and the chemical element symbol is Pt. It is a silver-white precious metal with a slightly higher hardness than gold, a density of 21.45 g/cm3 (at 20 ° C), and a melting point of 1768. C, it has many excellent characteristics, such as corrosion resistance, oxidation resistance, and beautiful colors. Because of the characteristics of platinum, it can be used to make inlaid jewelry, either in a beautifully shaped and tough platinum jewelry. Jewelry, especially on the platinum bottom, is set with sparkling diamonds, which are the most popular jewellery.
Types of platinum jewelry (common in the market)
PT990 jewelry, also known as pure white gold jewelry, has a platinum content of no less than 990 parts per thousand.
PT900 jewelry, its platinum content is not less than 900 parts per thousand.
PT850 jewelry, its platinum content is not less than 850 thousand.
Imprint of platinum jewelry:
Material and content mark: For example: PT900, indicating that the platinum content is not less than 900 parts per thousand.
Manufacturer's mark: For example: Jing E, indicating that a manufacturer produces.
Diamond weight: eg D0.26, indicating that the diamond inlaid has a weight of 0.26 carats.
Consumers should pay special attention to the imprint when buying jewelry. The platinum (platinum) jewelry is distinguished from the white K gold jewelry. The white 18K gold mark is 18K, and the platinum (platinum) is Pt.
Basic knowledge of silver jewelry:
Silver, the chemical element symbol is Ag, which is a silver-white precious metal with a low hardness, a density of 10.5%/cm3, and a melting point of 960. C, has good electrical conductivity, ductility and thermal conductivity, in addition to the use of electronics, medical, and photographic industries, but also for the manufacture of currency, jewelry, utensils, etc.
Silver jewelry classification (common in the market)
S990 pure silver jewelry has a silver content of no less than 990 thousand.
S925 silver jewellery contains no less than 925 parts of silver.
Imprint of silver jewelry:
Material and content imprint, such as: S925, indicates that the silver content of the jewelry is not less than 925/25.
Manufacturer's imprint such as: Beijing A, indicating that a manufacturer produces
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