1, classification: divided into pure gold (pure gold) and k gold.

There are 99.99% and 99% gold in the market, of which the former is "49 gold" and the latter is "29 gold". At present, the highest purity gold is 99.9999%. K gold refers to adding a certain proportion of silver, copper, zinc and other metals to gold for fusion, so as to increase the strength and toughness of gold.

2. Calculation method of K gold:

The gold with the highest purity is 24K, and the gold content of 1K is 4. 166%. Generally, there are 24K, 22K, 20K, 18K, 14K, 12K and 9K, among which 18K and 14K are the most common, with gold contents of 75% and 58.33% respectively.

3. Identification of gold ornaments:

(1) Look at the color: The higher the purity of gold jewelry, the darker the color.

(2) Balance weight: The specific gravity of gold is 19.32, which is heavier than silver, copper, lead, zinc, aluminum and other metals. It should feel heavy in your hand.

(3) Look at the hardness: pure gold is soft and low in hardness. You can draw shallow marks with your nails, leaving teeth marks after biting, which is easy to bend.

(4) Listen to the sound: When real gold with a purity of over 99% is thrown on the hard ground, it will beep, without rhythm and elasticity.

(5) Burning: Jewelry burns red but does not melt, and changes color after cooling. The lower the color, the stronger the color.

(6) Look at the sign: domestic gold is purified and prepared according to international standards, and stamped, such as "pure gold" is "24K" or "all red" and gold is "18K".

4. Gold-plated, gold-plated and imitation gold ornaments

(1) Gold-plated ornaments: a thin layer of gold foil is rolled on the surface of the blank by mechanical method, which contains copper, silver, nickel, copper-zinc alloy and so on. The thickness of gold plating is generally 10-50 microns.

(2) Gold-plated ornaments: In a special plating bath, the blank is plated with a thin layer of gold foil. According to the regulations, gold-plated ornaments must indicate the thickness of the gold-plated layer. For example, P4AU means that the thickness of the gold-plated layer is 4 microns. Due to the weak binding force of gold particles, it is easy to corrode and will soon change color.

(3) Imitation gold jewelry: also known as secondary gold jewelry, which is golden in appearance and made of copper, nickel, zinc and other metals, and does not contain gold.

(3) Silver ornaments:

1, classification: pure silver, textured silver and colored silver by color.

2, simple identification: the color is over 97%, the skin is white and delicate, and the luster is soft and pleasing to the eye; The skin color of the weak is bluish white or gray, sometimes it is yellow, black and other variegated colors, and the color is dull.

(4) Platinum

1, classification:

Common platinum in the market is divided into PT900 and PT950, with platinum content of 90% and 95% respectively, and the rest are other rare metals such as palladium, rhodium and nickel. PT is the chemical element symbol of platinum.

2. Why is platinum more precious than gold?

Because platinum is a rarer metal than gold, the annual production of platinum is only 5% of that of gold. In addition, processing platinum jewelry also requires a high level of technology.

3. What's the difference between platinum and platinum?

White gold is actually an alloy, which is generally formed by the fusion of gold and other white alloys. The highest purity gold on the market is 75%. The white color of platinum is not natural, and it may fade over time. Platinum is a natural white precious metal, and its value is much higher than that of white gold. Platinum cannot be compared with platinum in purity, rarity and durability. The simplest way to distinguish the two is: platinum ornaments are generally marked with "PT900" and "PT 950" on the back; However, platinum jewelry cannot be marked with the "PT" logo.

(5) Provisions on the Administration of Appraisal of Gold and Silver Jewelry:

1In March, 1999, the State Bureau of Quality and Technical Supervision issued the Regulations on the Administration of Gold and Silver Ornaments, requiring all gold and silver ornaments to have marks, including imprints and other marks. The imprint includes the name of the material and the gold content (silver, platinum). If the weight of a single piece is less than 0.5 g or it is difficult to mark, the imprint content can be exempted. The imprint should be printed on the gold and silver ornaments by the producer. Other marks can be one or more, including name, material name, gold content (silver and platinum content), name and address of producer, product standard number, product quality inspection certificate, weight of products sold by weight, etc.

Imported gold and silver ornaments need not be marked with the name and address of the producer, but should be marked with the origin of the product and the name and address of the legally registered agent, importer or seller in China. The place of origin here refers to the final production, processing or assembly place of gold and silver ornaments.

Second, the identification and appraisal of jewelry

(1) Jewelry and Jewelry Accessories

Jewelry refers to rare, beautiful and precious natural substances such as diamonds, pearls, rubies, sapphires and ivory. Jewelry refers to all kinds of ornaments polished, carved, inlaid and strung with all kinds of precious stones.

(2) Classification of jewelry and jade

1, inorganic jewelry mainly includes:

(1) Natural jewelry: precious gems mined from mines and polished to make jewelry and handicrafts, such as diamonds, aquamarine and jadeite.

(2) Semi-precious stones are ornaments that use similar substances to replace and simulate precious stones. Generally, it refers to middle and low grade gems with hardness below 7 degrees.

(3) Synthetic jewelry: It is based on a natural gem and made of materials with the same properties as natural gems through scientific methods. Such as artificial rubies, sapphires, emeralds and Jin Gangzuan.

(4) Gemstone filling: In fact, it refers to artificial lead-containing glass, plastic products and other beautiful substances as gems, which can not be compared with the above-mentioned gems in terms of color, hardness, chemical properties and value.

2. Organic jewelry is evolved from living things. Such as pearls, corals, amber, coal concentrate, etc. Its main components are carbon, hydrogen and oxygen, which are combined in different proportions.

(3) Identification of jewelry

1, specific color: natural jewelry is natural in color, and synthetic gems are often over-decorated and unnatural.

2. Clarity: Clarity refers to the transparency and cleanliness of gemstones. Generally, synthetic jewelry has fewer defects and cleaner interior.

3. Look and ponder: that is, the process of jewelry processing. After polishing, natural jewelry has smooth surface, strong refractive index and crisp angular lines; However, synthetic gems often become rough and dull after polishing.

4, card weight method: through weighing to identify the same volume of jewelry. If zircon and diamond with the same volume are weighed at the same time, the heaviest one is diamond.

5. Light identification: put the jewelry under the desk lamp for inspection, put down the lampshade so that the light does not directly hit the eyes, and then put the jewelry on the edge of the lampshade, half under the light and half in the dark. Under the light, the internal defects can be illuminated by light.

(4) Cleaning of jewelry

1, high hardness materials, such as diamonds, emeralds, rubies and sapphires, can be washed with clean water. If it is not ideal, it can be cleaned with cleaning solution, that is, first soak the jewelry in a small basin of warm water with neutral detergent, brush off the dirt on the back with a brush, then clean the filter paper with warm water, and finally dry it with a dry cloth.

2. Materials with medium hardness, such as jade and garnet. Only use a soft brush to gently brush the stain with washing liquid, then wrap it with absorbent paper or gauze, suck up the sewage, then pour alcohol and water into the soft cloth, gently rub the ornaments, and put them in the shade to dry or air dry.

3. Jewelry with high water absorption such as amber, coral and turquoise with low hardness should not be washed by water. It will crack when heated, and it should not be exposed to alcohol, oil and vinegar. Wipe the stains with flannel at ordinary times, and pay attention to reducing friction.

4. For pearls that are not wear-resistant and weak in acid and alkali resistance, try to avoid sun exposure, rain and sweat stains. Wipe it with a soft cloth after each use, or rub some cold cream first, then wipe it with a soft cloth, and the effect is better.

(5) Brief introduction of several kinds of jewelry and jade

1, diamond

(1) General characteristics of diamonds: Diamonds are natural equiaxed minerals crystallized from carbon in mantle magma. The main component is carbon, with Mohs hardness 10, density of 3.52g/cm3, refractive index of 2.4 17 and dispersion rate of 0.044.

(2) diamond color grading: in a specific experimental environment, the samples are compared with the known color grades of colorimetric stones, which are divided into grades of D, E, F, G, H, I, J, K, L, M, N, etc. 1 1. ..

(3) Classification of diamond clarity: The size, quantity and distribution of internal and surface defects of diamonds and their influence on diamond luster were observed with a magnifying glass of 10 times, which was divided into five grades: LC, VVS, VS, SI, P * * * and 10.

(4) Diamond cutting classification: According to the cutting and grinding ratio and the degree of modification of each part, it is divided into three grades: very good, very good and general.

(5) Carat weight of diamonds: those below 0.2 carats may not be classified. 0.2 carat-1 carat can be classified by both loose diamonds and inlaid diamonds. Diamonds larger than 1 carat must be classified in detail in terms of color, clarity and cut according to the classification standard of loose diamonds.

(6) Diamonds: Diamonds smaller than 0.2 carats can be preliminarily classified according to the Standard of Diamond Quality Classification Rules, and divided into five grades according to clarity and color, namely, excellent, very good, good and good.

(7) 4C standard for diamond identification:

Carat weight

Big diamonds are rare and expensive, while small diamonds are dazzling.

The weight of diamonds is measured in carats. 1 carat = 100 min = 200mg = 0.2g. Therefore, 0.75 carat is also called 75 points, and 0.02 carat is also called 2 points. Other things being similar, with the increase of diamond weight, its value increases geometrically; Diamonds with the same weight will have different values due to different colors, cleanliness and cutting. Good quality diamonds come in different sizes and shapes.

CLARITY (clarity)

Crystal clear and pure beauty is hard to find.

Diamonds are crystallized from mantle magma deep in the earth, with complex environment, diverse components and extremely high temperature and pressure. After hundreds of millions of years of geological changes, there are inevitably various impurities or defects inside. The color, quantity, size and location distribution of these inclusions have different degrees of influence on the clarity of diamonds.

Generally, according to the procedure of making defects on the inside and surface of diamonds with 10x magnifying glass and its influence on their luster, the clarity levels of diamonds without inlaid diamonds are subdivided into LC, VVS 1, VVS2, VS 1, s1and S 12. Diamonds are divided into excellent, very good, good and good, and there are generally five grades.

Color (color)

Colorless, elegant and rare.

Diamonds have many natural colors, from precious colorless (white after cutting), rare light blue and pink to common light yellow. The more transparent and colorless it is, the more white light penetrates the kidney and becomes more colorful after refraction and dispersion.

The grading of diamond color is determined by technicians after repeatedly comparing the diamond to be graded with the standard color stone in the grading environment of professional laboratories.

The whitest diamond is classified as D (starting with the first letter of the diamond). The color of diamonds is divided into 1 1 grades, which are D, E, F, G, H, I, J, K, L, M and N in turn.

incision

Exquisite carving and shining

The brilliance of diamond is attributed to its unique high refractive index and high dispersion. However, uncut diamonds are just plain in appearance. Only through accurate calculation, careful design and perfect cutting and polishing can the light be fully reflected to the top surface and the beauty of diamonds be fully displayed. Diamond is the hardest substance, indestructible, never worn, once cut and polished, it will shine forever.

The way to judge the quality of cutting is to pick up the diamond and stare at the jumping light on it. The exquisite diamonds of lathe are dazzling and will not be lost because of inlay or different styles. The level of lathe work is divided into: very good, very good and average.

(8) Simple identification method of diamonds

Diamonds are the king of gems. It is lipophilic. You can brush the surface of the diamond with oily stationery, leaving a diamond line. If the scratches gather into water drops, it is a fake diamond. You can also brush the diamond surface with water-based stationery. Small water droplets on the surface of diamonds can last for a long time, while fake diamonds will disperse in a short time. You can also wear diamonds on your hands. You can't see palm prints through natural diamonds, but fake diamonds (such as zircon) can. Diamonds generally emit silver light, while zircon emits blue light. If real diamonds are placed on black paper, they are still silvery white, while zircon is as pale as glass.

2. Emerald

Jade is the king of jade, and it is a mineral combination with jadeite as the main component. Color is its main feature. As far as jadeite is concerned, the green color of jadeite can't be blue, but it can only deviate from yellow. The highest grade jadeites are jadeite, emerald, apple green and Mabel Miao. Signs are divided into three categories: A goods, B goods and C goods.

A goods are pure natural jadeite, commonly known as "real goods". C goods are obviously mishandled, such as dyed white and sad green, which is a typical "fake". Goods B are processed by incomplete methods, such as mechanical or chemical methods to remove defects, and the holes left are filled with colored plastic, and then waxed and polished to become a surface with no defects in appearance, but the modified surface will change color and deteriorate with time, and eventually become defective, so this kind of goods is also a fake.

Key points of jadeite identification:

(1) "Emerald" and structure: "Emerald" is what people in the industry call "flying wing", which is a star-shaped, linear and flaky flash on the cleavage surface of jade surface. Jade with rough structure is easy to see, while jade with fine structure needs a magnifying glass.

(2) Jade is rich in color and unevenly distributed, with different shades of green or black on a white background, and lotus root powder, oil blue and bean green on a green background.

(3) Gloss: It has glass luster or grease luster. Jade with good transparent water head is moist and thoroughly brewed, which is not available in other jadeites.

(4) Smooth: its structure is compact and delicate, its hardness is high, and its polished surface is smooth.

(5) Cool feeling: The jadeite surface has a cool feeling when attached to the face or lips.

(6) Weighing: When weighing by hand, there is a feeling of falling hands. Generally, green jade and Xizhou jade are lighter.

3. Ruby

Ruby, that is, red corundum, is one of the five greatest gems in the world (diamonds, rubies, sapphires, emeralds and emeralds), and usually contains some gas-liquid or mineral inclusions. Its best color is called "pigeon blood red", which is produced in the ancient pastoral areas of Myanmar.

The difference between (1) and synthetic rubies is that the synthetic rubies are uniform in color, too bright, with few internal defects, often large in size, and occasionally arc-shaped growth lines can be seen.

(2) Difference from red glass: The color of red glass is uniform, without dichroism, circular bubbles, vortex lines, etc. Visible under a magnifying glass, there are traces of melting and casting on the surface, with low hardness, and there are often traces of corrosion on the prism surface. In addition, the glass has low density and light handle.

4. Crystal stone:

How to distinguish off-duty from crystal is the key to identification. Both are mainly composed of silicon dioxide. Glass is formed in a short time under artificial conditions. Because the air is not exhausted, bubbles often form inside. Rock crystals often contain gas-liquid inclusions instead of bubbles. Specifically distinguish from the following aspects:

(1) Different luster: glass products are whiter and brighter, and look more beautiful than crystal.

(2) The rock crystal is anisotropic, and it turns into four bright and four dark at 360 degrees under the polarizer. Glass is an isotropic body, which turns 360 degrees under a polarizer and becomes completely black.

(3) Under the ultraviolet fluorescent lamp, rock crystals have no fluorescence at both long and short wavelengths, while glass shows strong fluorescence.

(4) The crystal stone feels cold and the glass is warm.

Crystal is a kind of transparent timely crystal, which is hexagonal and columnar, with high hardness and strong reflective ability. Pure crystals are colorless transparent body, which is not so clean once impurities penetrate.

Artificial crystal is a mixture of quartz sand, alumina and other minerals, and polished by fine cutting technology. All-aluminum crystal is the best artificial crystal. Because this kind of artificial crystal is more complicated, it is more expensive than rock crystal. On the other hand, crystal has a great market because of its natural beauty.

Some reports specializing in the medical function of crystal claim that crystal necklace can reduce fever, lower blood pressure and prevent breast cancer; Crystal glasses can improve eyesight, strengthen brain and refresh. Wearing crystal ornaments for a long time has magical effects such as beauty and regulating human functions.

5. pearls

There are two kinds of natural pearls and cultured pearls. The former is a naturally growing bead in mussels, also known as real beads. The latter is formed in cultured mussels and is divided into wrapped beads and light beads. Bao Suzhu is a small ball wrapped in a layer of fish scales or wax skin, which looks yellow and dull. You can scratch the skin with a knife or needle to expose the ball inside. Synthetic beads are caused by improper placement of the bead core, and the bead solution only covers part of the bead core. Two pearls can be used for identification. The fake feeling is very smooth, and it really has a "astringent" feeling. The advantages and disadvantages of pearls lie in their appearance, brightness and color. Excellent products must be smooth and bright, and silver with a little pink iridescence is the best. In addition, the identification of pearls should be carried out under the natural light with sufficient light and no glare, wearing plain clothes and trying to support the interference of foreign colors on the primary colors of pearls. Natural black pearl is very precious because of its charming color and low yield, and it is a treasure among pearls.

Natural black pearls are not pure black, but dark blue black or bronze black with a rainbow-like flash, while dyed black pearls are pure black with dead color. Observing the surface of pearls with a magnifying glass, you can often see corroded pearls.

When not in use, wash the sweat off it with neutral detergent, rinse it with clear water and dry it, and then store it in a box. The bead layer is thin and soft, so try to avoid friction and impact with metal or hard objects, and do not expose to the sun for a long time.

(6) National standards for jewelry and jade.

GB/T 16552- 1996 name of jewelry and jade.

GB/T 16553- 1996 jewelry and jade identification

GB/T 16554- 1996 diamond classification