1。 General solid method of jade
The identification of jade ornaments should be based on hardness, transparency, color, luster and spots. Real jade is very hard and wear-resistant, crystal clear, pure and beautiful in color and sparkling. If you can see cracks, fibrous cotton threads or dark wounds in jade, it is inferior jade. All fake jade has wrinkles on the surface and bubbles inside, which is light in weight and low in hardness, and the sound is crisp when knocking each other.
Agate Jian Zhen method
Agate is a rare and precious thing, and there are many fakes on the market. Most of them are made of refined turpentine, mirabilite and broken glass. To identify the authenticity, it must be rubbed in the palm of your hand, and the color, shape and smell remain unchanged. However, some people think that everything that is prone to fever after friction is genuine, which is misunderstood and unreliable.
Method for naked eye identification of gemstones
Gems can be divided into natural gems and artificial gem. When we choose precious stones and jewelry, how can we identify them with the naked eye? Natural gemstones are generally soft and natural in color, and sometimes the colors are very mixed. Several kinds of * * * in a gem, the pattern is irregular, but very delicate. Observing the gem with naked eyes under strong light, or carefully observing it with a magnifying glass for more than 5 times, sometimes you can see cotton wool, reticular or tree-root inclusions and small cracks in the gem, and occasionally you can see obvious flat growth lines. Some gems feel cold and slippery, and look wet, as if they had been soaked in oil. A good gem has the effect of "cat's eye" and "starlight" after polishing, that is, there is a white line in the gem, just like the white line in the cat's eye under strong light during the day; "Starlight" is a gem that rotates in the sun, and the reflected light shines like the blink of an eye of the stars at night. Artificial gem is generally bright, uniform and pure. After polishing, the luster is dazzling and the color consciousness is strong. Because some rare earth elements are added, there are monochromatic ones, such as black, red and yellow. There are also composite colors, such as rose red and sauce purple. But there will never be a phenomenon that several colors of natural gems are in the gem. In addition, some gems have obvious circular bubbles and traces of synthetic growth products; Obviously, the growth line is linear; Larger particles; There are many specifications of the same color; Harder ones, generally above Mohs level 6, can't be carved with a knife. Instead, these stones can mark glass.
Identification of true and false gems
In the sun, with a light silver pot or white satin as the lining, put the gem at a height of about five inches from the lining to make it exposed to the sun. If the light passing through the gem shows the appearance of the silver wing of Venus in the lining, it can be concluded that it is genuine. If it is a fake gem, a shadow will appear on the lining. If you put the gem in your mouth for a while, you will drool, not only will you not feel dry, but your mouth will be very cold. If the gem itself gets hot, you can conclude that it is genuine.
Emerald Jian Zhen method
Fill a bowl with clear water, and put the gem into the bowl, which can make the whole bowl appear pale green and is a real emerald; Or put Jian Zhen's gems in a copper basin, enclose them with paper, and light the white paper with fire. If fire can turn green, it is true jade; Or prepare a pot of burning coal, and put Jian Zhen's gems into the burning coal. When the charcoal smells, the emeralds will go out immediately.
Yupu identification method
Whenever people see a piece of jade (a stone containing jade), they often suffer from the inability to identify whether it contains beautiful jade, which is really a pity. In fact, its identification method is also very simple. If precious jade is hidden in the stone, look at the stone in the light at night. If there is light in the stone, just like the light color of the rising sun, it means there must be precious jade in it. On the contrary, it is not.
Diamond identification method
Real diamonds glow green in the dark, just like sparks from wires. If it is a fake diamond, it can only emit a small amount of white light or even no light. Even if it glows, it looks dark and there is no flicker. In addition, the hardness of the diamond is the greatest. When the real diamond and the fake diamond are cut, the properties of the diamond will be obviously different immediately.
2。 Simple identification method of common jade and nephrite
1. Rock characteristics: nephrite is a metamorphic rock, which is formed by contact between magnesium marble and intermediate-acid magma. The main minerals are amphibole and a small amount of actinolite. The chemical composition is Ca2(Mg, Fe)5Si8O22(OH)2. Block structure, fiber interwoven structure, delicate aphanitic texture.
The color is mainly white, which can be green, brown, yellow, black, gray, cyan and other colors. The tremolite content in white jade is above 95%. The contents of green actinolite and epidote in green and cyan nephrite are increased, and the total content can reach more than 10%.
Nephrite is oily and its fracture is serrated. Translucent to opaque. Good toughness, hardness 6-7, specific gravity 2.95. The refractive index is 1.6 1.
According to different colors, it can be called white jade and sapphire. As shown in Figure 57, it is a green nephrite ornament produced in Xinjiang, commonly known as jasper.
Because nephrite is mainly produced in Hotan, Xinjiang, it can also be called Hotan jade. According to national standards, the name of "Hetian Jade" does not mean that it is produced in Hetian.
2. Identification features: high hardness, strong toughness and heavy specific gravity. Grease luster, fiber interwoven structure.
3. Common white jade fakes and identification: White jade fakes often include white marble, quartzite jade and emulsified glass. In addition, dushan jade and serpentine jade are similar to white jade. Marble jade has low hardness (3) and low specific gravity (2.7). Because of the rough surface of marble, there is no oily luster like white jade, and the surface is often coated with a layer of liquid wax, which confuses the vision. This waxed marble has a wax-like luster and will get your hands dirty. Leave it for a while until the wax evaporates and the marble regains its earthy luster. Marble has a granular structure, and sometimes bands with different shades can be seen. Quartzite jade has high hardness (7) and low specific gravity (2.65). Granular structure, dry luster, no oily luster of white jade. Emulsified glass is glassy and has no unique structure of rock. The naked eye can see that there are bubbles inside. Generally, the hardness is small (5) and the specific gravity is small (2.4).
4. Nephrite resources: The most famous nephrite producing area in China is Hotan, Xinjiang. Nephrite is also produced in Qinghai Province, Russia and Canada.
Hetian jade is mainly distributed in Altun Mountain and Kunlun Mountain in southern Xinjiang, starting from Qiemo County in the east and reaching Tashkurgan in the west. The length of the east-west ore belt is 1500 km. It is a contact metamorphic deposit occurring in the contact zone between Precambrian magnesium marble and Variscan intermediate-acid granite. Hetian jade can be divided into seed jade, landscape jade (or Gobi desert jade, new mine jade) and mountain material jade (primary mine). Sheep fat white jade in seed jade is moist as fat, and mineral crystals are almost invisible to the naked eye, showing aphanitic texture. The color is calm and dignified, luxurious and unambiguous, and the light is restrained and frank. Hetian jade seed jade often has a little sweet-scented osmanthus skin, jujube skin, autumn pear skin, brown sugar skin and crow skin. This is also a major feature of Hetian jade. When making jade articles, clever colors and carvings will greatly enhance their artistic value. As shown in Figure 58, it is a white jade boy toy with yellow skin. Mountain jade is not as moist as seed jade, slightly bluish gray, dry and cracked.
Qinghai white jade is produced in the southwest plateau hilly area of Golmud City, Qinghai Province, and is mainly made of mountain materials. Qinghai white jade has good transparency and tender but not old color. Often contain more stone flowers, flocs, spots and so on. White is usually yellow gray, smoky gray or light green. The greenish one is similar to the emerald one.
Russian white jade is produced in Lake Baikal, and its color is similar to that of Hetian jade, but it is not moist. Generally, the structure is loose and has a sense of glass. Good Russian white jade, with high whiteness and slight grease, is very popular with collectors. The color of ordinary Russian white jade is gray and yellow, and sometimes it is smoky gray.
Canadian nephrite is green, commonly known as jasper. Colors range from light grayish green to dark green, and dark green often contains black spots.
3。 Some simple methods to identify jade
Do you really want to buy some jade, but you are worried about buying fake and shoddy goods! So let's give you some simple ways to identify jade now.
1 water identification method → drop a drop of water on jade, and it will become dew after a long time, which is the real jade; The water droplets disappear quickly, which is a fake.
2 Touch by hand → Real jade will feel cold and lubricated if touched by hand.
Inspection method → Put jade in bright places such as sunshine and light. If the color is clear and the green is evenly distributed, it is a real jade.
3 tongue licking method → licking real jade with the tip of the tongue has a astringent feeling; Fake jade has no astringency.
4 Magnifier viewing method → Put the purchased jade under a magnifying glass to see if there are cracks. The jade without cracks is the best quality jade, followed by cracks. Even if it is real jade, the value of cracks is greatly reduced. The more cracks, the more obvious and the lower the value.
Tie a hair to the jade, and then burn the jade with a lighter. Hair is real jade, but it is fake or inferior jade! Because jadeite is a cool gem, it can fully absorb some heat given by the outside world.
Tools used in professional evaluation:
1 strong light. Magnifier is about 2 15 times. Portable microscope. 4 polarizer. 5 Charles color filter. 6 Antique appraiser
4。 Cui Fei Changshi
I. The origin of the name
The word jade comes from the jade bird. The male of this bird is bright red and the female is bright green, which is called kingfisher. Because the jadeite produced in nature is mostly green and red, the word "jadeite" has gradually changed from bird to jade. The color of jadeite is natural and changeable, and it is integrated with nature, representing the vitality and youthful vitality of all things, and is deeply loved by the oriental nation, especially the Chinese nation.
The ancients regarded jade as a treasure and regarded it as a precious ornament. Ancient medical books said that "jade is the beauty of stone, sweet and non-toxic", and that jade is the most abundant substance in human body. Therefore, jade is not only used as jade locks, jade fingers, bracelets, anklets, hanging chains, snuff bottles, decorations and decorations, but also used for health preservation and fitness.
Modern science and technology show that jade contains trace elements beneficial to human body, such as zinc, magnesium, copper, chromium and manganese. Wearing jade often can make human skin absorb trace elements, which is helpful to the coordination and balance of physiological functions of human organs. Some jade has the physical characteristics of absorbing light during the day and emitting light at night. When the jade spot is aimed at a certain point in the human body, it can stimulate the meridians and dredge the viscera, which has obvious health care function. There is a "pension hole" on the back of the old man's wrist. Wearing jade bracelets can play the role of massage and health care, which can not only improve the symptoms of blurred vision of the elderly, but also store vitality and nourish the spirit. The oral cavity contains jade. With the help of the synergistic effect of the nutrients contained in saliva and lysozyme, it is helpful to promote fluid production to quench thirst, remove stomach heat, relieve annoyance, nourish the heart and lungs, moisten the throat and raise hair, and store qi to nourish the mind.
2. The color of jadeite
There are white, green, purple, red, yellow and black.
3. Types of jadeite
According to the characteristics of color, transparency and texture, jade can be divided into many types.
1. Old cellar species: the color is thick, positive, bright and even, with fine texture and good transparency. This is the most precious wealth.
2. Ice species: the water head is excellent, crystal clear, light or colorless, and it is a "colorless" jade, which belongs to a high-grade variety.
3. Hibiscus species: although the color is light, it is very positive, without yellow tone, and the jade is delicate and attractive, which belongs to middle and high-grade varieties.
4. Golden seeds: green is bright and bright, which makes people feel that emeralds contain golden light and are arranged in a filiform and intermittent manner. Because of its good head, it is highly respected.
5. Gan Qing species: thick and pure green, poor transparency, dry foundation, rough jade and short columnar mineral particles.
6. Flower-green species: green is irregularly distributed in veins or spots, and it is a widely distributed jadeite, belonging to middle and low-grade varieties.
7. Oil green species: good transparency, fine jade, oily luster on the surface, dark green, blue-gray tone, giving people a very dim feeling, belonging to middle and low-grade varieties.
8. Horse tooth species: the mineral particles are white and granular, with poor transparency and rough texture, belonging to low-grade varieties.
4. Quality evaluation of jadeite jade
There is a saying in China that "gold is valuable, but jade is priceless". Why is it so difficult to quote jadeite? Because unlike other gems, jadeite is not a single crystal, but a mineral aggregate, and the types, colors and particle sizes of the minerals that make up the aggregate are often inconsistent, which makes the appearance of jadeite varied. In addition, due to the influence of many geological processes in the later period, even on the same piece of jade, the thickness and color of the particles are uneven. As the saying goes, "People have thousands of faces, and jade has thousands of faces." Therefore, the evaluation of jadeite is very difficult. For carvings, its artistic conception and processing skills make it more difficult to evaluate jadeite.
Generally speaking, the following factors should be comprehensively considered when evaluating jadeite:
1. color: color is the primary factor that determines the value of jadeite. If the color is a little worse, the value is much worse. Therefore, it is very important to observe colors correctly. Emerald will be brighter and more saturated under incandescent lamp, which is called "beauty under the moon, jade under the lamp". The same piece of jade will be relatively bright and dark when observed in the sun. Usually people take the color observed in natural light as the standard. To evaluate the color of jadeite, the following four factors should be considered:
① Dense: refers to the saturation or depth of color. People and the elderly from northern China, Taiwan Province Province and Japan prefer darker colors, while Singaporeans and young people prefer lighter jadeite.
② Positive: refers to the purity of color. Slightly yellowish green will not affect the brightness of green and the value of jadeite, but too much yellowish green will affect the value of jadeite. Because blue will reduce the brightness of green, if it is blue, it will have a great influence on the value of jade. Gray-green makes people feel black and dirty, and its value is much lower.
3 fresh: refers to the lightness of color. It is the most important factor that constitutes the aesthetic feeling of jade color, and it is also the most difficult factor to find. If the brightness is similar, the value will be much worse. If different people have different shades of color, the requirements for brightness are the same, that is, the higher the brightness, the better. The intensity of light source has a great influence on the observation of brightness. Brightness is high under strong light source and low under weak light source.
④ Average: refers to the uniformity of color distribution. Because jadeite is composed of countless tiny crystals, the color of each crystal may be different, so the color of jadeite is rarely uniform. Obviously, the higher the uniformity, the higher the value.
But when green, red and purple appear harmoniously, it is commonly known as "Fu Lushou". Because of its rarity, this jadeite is of high value.
2. Transparency: refers to the degree to which jadeite allows visible light to pass freely. Due to the different thickness and combination of jadeite particles, the ability to allow light to pass through is also different. If most of the light can't penetrate, the color of jadeite appears dull, which is called "dry" in jargon. If most of the light passes through the jade, the transparency will be high, which will make the jade look very crystal clear and have the feeling of "watery", which is vividly called water foot in jargon. Appreciating jade with high transparency will make people feel intoxicated. This kind of jade has a moist feeling, as if the color is alive and can be released around. In jargon, transparency is also called "species". Poor transparency means poor planting, and there is a saying in the industry that "good planting covers three ugliness":
(1) can make light-colored jadeite appear crystal-clear and beautiful;
(2) colors that are not uniform enough can be made uniform due to mutual reflection;
(3) It can make jadeite which is not delicate enough to see obvious particles.
3. Volume: Under the same conditions of color, species, bottom, workmanship, cracks, etc., the larger the volume, the more expensive it is, which has a greater impact on high-priced jadeite. For example, beads and bracelets need more raw materials to make. If the bracelet is made of ring material, the value of the bracelet will increase geometrically. No wonder the bracelet can be auctioned to100000 Hong Kong dollars. At the same time, the evaluation cost of supporting products is much more expensive than that of single products.
4. Workmanship: For jewelry such as ring faces and earrings, it is required to cut properly and polish well; For pendants and ornaments, craftsmen's ingenious ideas and skillful skills will play a decisive role.
Verb (abbreviation of verb) The origin of jadeite.
More than 95% of jadeite in the world is produced in the Wulong River basin in Meng Gong area of Myitkyina in northern Myanmar. So Myanmar is the only jadeite mine in the commercial sense.
Sixth, identify the authenticity of jade.
At present, jadeite sold in the market is divided into the following categories:
Commodity 1. A: Natural jadeite, the original stone has not undergone any chemical treatment, only carving and polishing. The advantage of this jadeite is that it is naturally generated and will not change with time, maintaining a variety of elements beneficial to the body.
2. Goods B: Soak natural jadeite with medicinal liquid to increase the transparency of jadeite and soak it green at the same time. With the passage of time, the green color of this treated B-quality jadeite will gradually fade and become dim. Usually it will change beyond recognition in two or three years. This jadeite is difficult to identify because of its high degree of simulation.
3.AB goods: between the two, it is more difficult to identify the fake original stone.
4.c goods: fakes made of glass or organic materials.
For these three kinds of unnatural jadeites, the following identification methods can be used respectively:
Commodity 1. C:
① Hardness distinction: The hardness of natural jadeite is 6.5-7, which is rarely seen in nature or cheap synthetic materials. So hardness can be used to distinguish C goods. The method is: scrape the glass with jade. If it is real jade, there will be scratches on the glass, but jade is fine. If jadeite is also deslagging, it must be C.
② Bubbles: Some synthetic materials will inevitably have small bubbles during processing. If bubbles can be seen with the naked eye or under a microscope, it must be false.
Price: If you take a fancy to a beautiful jade, but the price is very low, you should check it carefully at this time, and it is likely to be fake. All the items listed on this page are very expensive. You can compare it.
2. Goods B and AB:
B goods are hard to distinguish, so now, even some jewelry stores are selling B goods. But as long as you touch jade often, it is still easy to tell.
Generally speaking, commodity B has the following characteristics:
(1) The directionality of green is destroyed, and some are yellow, floating and unnatural;
(2) Grooved criss-crossing ditches are generated on the surface.
Naturally occurring things must have some impurities and imperfections. If there are no obvious shortcomings, be careful.
④ Price: Because B goods are unstable, merchants are always eager to sell, so be careful about lowering prices or lower prices.
If you have instruments, you can also refer to the following items:
If you see strong yellow-green, blue-white fluorescence under ultraviolet light, it means "B goods"
Identification method of fake jade
There is only one box of fake jade in the jar mentioned above. Although jar jade is very similar to jade, careful observation will reveal that it has pores. Compared with real jade, fake jade has tiny flying feet on its surface, which is not moistened for a long time, and it is brittle no matter how it is rubbed manually.
The fake jade that the stone pretends to be is similar to jade at first glance, but it is not moist, has excessive bright colors, is opaque and has lower hardness than jade. Because the hardness of real jade is low, it will not change no matter how it is rubbed. The more it is rubbed, the more moist it becomes. As soon as the stone is rubbed, it changes immediately and stripes appear.
In addition to the above methods, the identification of fake jade mainly depends on the quality of jade. In the era of underdeveloped science, the ancients could not identify the mineral composition of gems and jade, so every time they met gems, they should be distinguished by color. Today, although we have the knowledge of mineralogy, the color of jade is still one of the important basis for us to identify jade, because color is the most intuitive and easy to identify, and it can be seen with the naked eye.
The various colors of jadeite are related to its mineral composition. In other words, the color of jade is related to the absorption of visible light (white light) by minerals. At the same time, color is also related to pigment ions and crystal defects contained in minerals.
With regard to the colors of traditional jade and common gemstones in China, the jewelry and handicraft industry in China has accumulated a lot of experience after years of accumulation, and many vivid color names have appeared. For example, jadeite includes emerald green (similar to the color of jadeite), brilliant green (jadeite is not black), boxwood green (jadeite is yellowish), bright turquoise green (jadeite is bright), glass green (jadeite is transparent), Ying Ge green (the same color as Ying Ge feather), spinach green (thick but not bright), shallow water green (jadeite is light) and light sunshine green (light). Oil green (green and dark gray), lotus root starch (light pink and purple tone), violet (violet), chrome black (black green), white material (white) and jade material (full green).
Nephrite includes white (white jade), fat white (suet jade), bluish gray or bluish white (blue white jade), cyan (white gray, white green sapphire), yellow (topaz), green (emerald), black (black jade), colorful (nephrite opal produced in Taiwan Province Province), in addition to tiger skin jade, sugar jade and yellow-brown skin.
Lantian jade has green in white and yellow-green in white. The color is not uniform, often foggy and spotted.
Nanyang jade has white, green, purple, yellow, green, dark green, blue-green, pure blue, white in blue, white in green, milky white, purple white and so on. According to the statistics of Henan Geological Bureau, there are more than 30 colors.
Turquoise is green, grass green, yellow-green, white-green, pale white, light blue-green, sky blue, lake blue, and green with black spots and black lines.
Agate has many colors, such as red, bordeaux, brownish red, earth red, crimson, white, gray, gray, green, grass green, onion green, blue, blue-white, blue and so on, such as colored stripes or ribbons, which are various and varied.
Lapis lazuli is blue with purple tones, dark blue, dark blue, with Venus (containing pyrite) in the blue and white (containing calcite) in the blue.
Malachite is green, malachite green, dark green, light green and dark color, such as stripes, green and yellow-green.
Chrysocolla has light sky blue green, sky blue and turquoise.
Diamonds are colorless, white, black, purple, green, yellow, dark yellow, brown, yellowish brown, yellowish green, turquoise, blue and grayish black.
Ruby has red, light red, pink, crimson, brown red, blood red, rose purple and other colors.
Sapphires are blue, sky blue, light blue, dark blue, blue purple, purple, brown, yellow, yellow-green, colorless, gray and so on.
Emeralds are colorless, green, gray-green, yellow-green, yellow, gold, pink, emerald (emerald), sky blue (navy blue) and other colors.
Topaz has colorless, yellow, light yellow, wine yellow, blue, sky blue, light green, green, yellow-green and other colors.
Golden emeralds are colorless, yellow, light yellow, sunflower yellow, brown, tan, yellowish green, brownish green, swimming color (opal), discoloration (stone change) and so on.
Bi Sheng has red, crimson (double powder), light red, green, dark green, dark green, yellowish green, colorless, sky blue, grayish brown, cyan, blue, purple, swimming color (electric opal) and so on.
The garnet with purple teeth and black almandine is mainly red; Mainly red, but also rose red, thick red, black red garnet; There are green, yellow, yellow-green, green (Ural Emerald) calcium aluminum garnet; There are emeralds, calcium chrome garnets and so on.
Moonstone has many colors such as moonlight, white, gray, light blue, sky blue, green and swimming color.
The crystals are colorless, purple (amethyst), brown (tea crystal), black (ink crystal) and pink, and contain inclusions (crystals) of needle-like minerals such as green, black and yellow, and shiny crystals of phlogopite and hematite.
Fluorite is colorless, light blue, blue-green, green, yellow, yellowish green, purple, pink, green and other variegated colors.
As can be seen from the above, many jade and precious stones are the same and similar in color. When colors cannot be distinguished, it is necessary to identify them with the help of mineralogical knowledge and instruments. For example, the transparency and luster of jade, the luminosity of jade and precious stones, the specific gravity and hardness of jade, the optical constants of ancient five minerals, observing the microscopic world of ancient jade minerals, and identifying ancient jade by chemical analysis. Besides naked eye observation, the color, luster and transparency of jadeite must be measured by various instruments based on the knowledge of petrochemistry and mineralogy. Especially chemical analysis and electron microscope determination can not only accurately judge the quality of jade, but also infer the origin of jade. As long as the quality of jade is determined, all fake jade will be seen through.
Hey, hey, I don't understand either. Hope to know the experts to exchange.
How to read jade appraisal certificate correctly
How to read the jade appraisal certificate correctly and one of the most effective ways to identify the authenticity of jade is to let the seller issue the appraisal certificate of the national authority. The appraisal certificate of national authority has high accuracy in jade appraisal. It should be said that there are few "lost goods", and even if there is a problem, you can recover compensation. The "important technology" required of collectors is how to understand the various results on the appraisal certificate.
If the jadeite certificate issued by the national authority is natural grade A jadeite, the result is only "jadeite", and the words "grade A jadeite" and "natural" will not be marked. Please note the following aspects:
First, only natural A goods will issue a certificate of "jade" results.
Secondly, if it is B-quality jadeite, there will be an item marked as "Jade (Treatment)", "Jade (Bonding)", "Jade (B-quality)" or "Jade (Optimization)" in the certificate.
Third, the jadeite of C goods will be marked with "Jade (Dyed)".
Fourth, the word "jade" will not appear in the project of appraisal certificate. Just indicate the names of the substitutes, such as "artificial glass", "dyed quartzite", "Xiuyu" and "Ma Laiyu".
Fifth, certificates should be one-to-one correspondence, that is, one thing and one certificate, and certificates should have pictures and weights of goods.
Although some things come from a piece of raw material and look similar in appearance, jade ornaments are not exactly the same. One thing with a certificate can't prove the quality of the whole batch of things. In order to save costs, some merchants only use certificates as samples, and the goods in the photos are also very similar to the real thing. This does not mean that what they sell is natural and does not conform to state regulations.
Sixth, the certificate should also indicate some basic physical, chemical and optical characteristics of jadeite.
Refractive index: 1.66 (this is the unique refractive index of jadeite itself that distinguishes it from other gems);
Density: 3.33 (which is also the feature that distinguishes jadeite from other gems);
Magnification detection: fiber interwoven structure (this is the unique structure of jadeite);
Absorption spectrum: 437nm absorption line (unique absorption spectrum of jadeite);
Color filter inspection: no response (some dyed jadeite will turn red under the color filter);
Luminance: aggregate (jadeite is a kind of micro-mineral aggregate);
Fluorescence: None (some B goods will have fluorescence reaction after injecting glue);
Appearance characteristics: glass luster (some B goods will show waxy luster).
Finally, there must be the signature of the inspector, and most importantly, the certificate must have a steel seal or an anti-counterfeiting mark.
The two most authoritative appraisal institutions in Beijing are the National Jewelry Quality Supervision and Inspection Center under the former Ministry of Geology and Mineral Resources and the Beijing Gaode Jewelry Appraisal Institute under the former Ministry of Foreign Trade and Economic Cooperation. One thing to be reminded is that there are many certificates issued by businesses that are not authorized by the state, and such certificates may be discounted in accuracy and authority. According to the document No.001of China Gemstone Association in 2004, the nationwide sampling results show that at least 19 appraisal institutions have some problems such as deliberately raising the diamond grade and identifying quartzite as jadeite, and some appraisal institutions even have a large number of unqualified tests. These problems are not all limited to the level of detection, but artificial cosmetic surgery for some interests, and consumers should pay special attention.