Nephrite: Also known as amphibole, its hardness is 6-6.5 and its specific gravity is 2.55-2.65. Its main component is calcium silicate fiber mineral. Nephrite is most famous in Hotan, China. The color of nephrite is close to the solidification beauty of oil, while pure nephrite is white, delicate and moist. Secondly, nephrite contains a small amount of oxidized metal ions, which are blue, green and yellow.

Emerald: commonly known as jadeite, it belongs to pyroxene, and its main component is sodium aluminosilicate, with hardness of 6.75-7 and specific gravity of 3.2-3.3. It is mainly produced in Myanmar, but also in China and Yunnan. Jade is hard, dense and glassy. Emerald green, lavender, apple green and snowflake white are typical colors of pyroxene.

Topaz: It is a kind of yellow jade, subdivided into chestnut color, egg yolk and okra yellow. It is a rare and precious variety among jade materials. Its solid color is extremely rare.

Jasper: It is dark green jade, mostly yellow, gray or with small black spots.

Blue and white jade: blue in color and slightly blue in white, which is called pink skin blue. Its color changes from shallow to deep, and it is more complicated and changeable in jade materials, with the largest number of varieties.

White jade: white jade, flawless, shiny as suet, white and moist.

Hetian jade: It is named after it is produced in Hetian, Xinjiang. It belongs to amphibole, with Mohs hardness of 6-6.5 and specific gravity of 2.9-3. 1. Divided into mountain jade and seed jade. The structure is mainly fibrous, and the polished surface has different luster. According to different colors, it can be divided into white jade, topaz, jasper, jet, sapphire and other colors. Hetian jade is an important origin of ancient jade in China and the best jade material in the world.

Emerald: It is the jewelry name of pyroxene jadeite. Produced in the border area of Myanmar near China, the chemical composition of jadeite is sodium aluminosilicate, with a Mohs hardness of 6.75-7 and a specific gravity of 3.4, with a glassy luster. Colors are: green, yellow, red, purple, white, blue and so on. Generally, the red one is called Fei, and the green one is called Cui, commonly known as jade. General jadeite is opaque, but some jadeites with good quality are close to transparent body.

Agate: Its mineral name is chalcedony, which is an aphanitic mineral from the season. Its composition is silicon dioxide, translucent or opaque, with glass luster. The hardness is Mohs 6.5-7 and the specific gravity is 2.65. Its colors are: red, yellow, blue, green and white.

Lapis lazuli: Its chemical composition is sodium, aluminum and sodalite. "Blue" refers to its brilliant blue. "Gold" refers to Venus produced by pyrite contained in jade. The colors are unique blue, dark blue and light blue. Its raw materials are opaque, glass to greasy luster, hardness 5-6 Mohs, and specific gravity 2.7. It is brittle and easily smashed by heavy objects.

Tourmaline: It is a mineral product. The original stone is hexagonal transparent columnar spar. The crystal is short column, long column or needle, and its cross section is spherical triangle. Different conical surfaces are common at both ends of a cylinder. The chemical composition of tourmaline is silicate. Small volume, Mohs hardness 6.5-7, specific gravity 2.9-3. 1. Pink, fragile, acid and alkali resistant, glassy, transparent or transparent body, with electricity. Tourmaline is the scientific name of tourmaline gem. Its high quality can be used as gem and jade carving material. Colors are pink, light green, pink, light yellow and so on.

Crystal: This is a colorless and transparent prismatic crystal. Its chemical composition is silicon dioxide, and its hardness is Mohs 7. Specific gravity is 2.5-2.65. Glass is one of the favorite gems because of its good luster and acid and alkali resistance.

Xiuyu: produced in Xiuyan county, Liaoning province, named after it. Its main component is serpentine with low hardness, Mohs 3-4. It is soft, and its colors are light yellow, fresh water green, apple green and so on. It is opaque or translucent. Xiuyan jade has a large output and is the most widely used jade material at present.

Lantian jade: It is produced in Lantian, Shaanxi Province, and serpentine diopside is mainly used in lantian jade, which is opaque and has green, yellow-green, cyan and dark green. The hardness is about Mohs 4.5.

Nanyangyu: Also known as dushan jade, it is produced in Nanyang City, Henan Province. Its main components are calcium silicate and aluminum silicate. It is a rock containing many minerals, with a specific gravity of 3.29 and a hardness of 6-6.5. Mostly opaque or translucent, with glass luster. Due to the limited quantity, it has a very high collection value.

Turquoise: Today's craft name is "turquoise". It is an opaque mineral, and its components are basic phosphates of copper and aluminum. Because copper participates in the composition of turquoise, turquoise becomes sky blue and green. It has a soft earthy to waxy luster. The hardness is Mohs hardness 6. Specific gravity is 2.6-2.8.

Matters needing attention

The most basic jade species in China are dushan jade in Nanyang, Hetian jade in Xinjiang, xiuyan jade in Liaoning and turquoise.

How to distinguish the quality of jadeite from its appearance;

First, because the glass is very brittle and hard, its structure is loosely arranged, and it lacks the density and toughness of jade, so it can't stand strong and high-speed rotary carving. Therefore, high relief and round carving generally cannot be processed on glass.

Second, use a magnifying glass to find bubbles, even if you can only see one, that is, glass.

Thirdly, chromium oxide is added into the glass, and the color is close to ruby; Adding cobalt oxide, the color is close to sapphire; Adding chromium oxide and copper oxide, the color is close to emerald. There are many colors. However, its color tone is always relatively thin, lacking the oily and rich feeling of natural jade color. The more difficult varieties are mainly fake jade made of polymer materials. Its color can be adjusted at will, and it is difficult to find bubbles under a magnifying glass. It is said that the original appearance can be displayed on the infrared spectrometer, but the key to visual inspection is to see whether there are natural stone lines on the surface of the instrument, in addition to the general unrealistic destructive inspection, cracking to find the stone section, burning to see its reaction. After all, manual processing is unnatural and will be exposed under a magnifying glass.

● Identification, including new jade and old jade. The identification of new jade focuses on the authenticity of the variety, the quality of the texture and the fineness of the sculptor. Some technical contents have been talked about before. However, the identification of Lao Yu is unusual. In addition to several basic requirements, new jade also needs to know the production age and historical value of jade.

The confirmation of the historical value of jade is based on a clear era. Familiar with the common shapes, characteristic crafts and popular colors of jade in different times. Then refer to the papers on the characteristics of jade in a certain era, and get in touch with each other, and your jade dating level will be rationally improved. At this time, you should contact the real thing as much as possible and correct the parallax between the picture and the real thing in the book.

In addition, the judgment of the times allows a certain span on some jade articles. Because jade tools are precious and not perishable, as a family heirloom, early jade appeared in tombs hundreds of years later, and there are many precedents. The late period of the last era and the early period of the next era are not completely unified in style. Jade has no date, and subtle differences are normal.

Hand-carved, beautifully carved, smooth to the touch, perfect in jade, moist and oily, delicate and meticulous, full of aura, flawless, exquisite in carving and ingenious in conception.

The temperature of jade is relatively low and it is not easy to transfer heat. If you put it in your hand, you can see how the temperature changes slowly.

In fact, agate has three characteristics that a gem must have: beautiful color pattern, fine and hard texture and rare natural output, so it is of course a kind of jade, but it is not a real jade in a narrow sense. In this regard, Dr. Wang Chunyun's research also believes that since agate is called "ruby" or "ruby" in historical documents before the Eastern Han Dynasty, it has already explained that agate belongs to jade of course.