How jade is formed: The formation of jade generally goes through four stages:
1. Dolomite was deposited in the late Mesoproterozoic, about one billion years ago, which requires a lot of carbonate deposition, among which magnesium-bearing dolomite is one of the main sources of jade.
2. The regional metamorphic stage of dolomite is in Sinian at the end of Proterozoic. In extensive regional metamorphism, dolomite is transformed into dolomite marble.
3. The metasomatic alteration stage of dolomite is from Late Carboniferous to Late Permian in Late Paleozoic more than 200 million years ago. There are strong fault activities and magmatic activities in the global crustal movement, and intermediate-acid intrusive rocks invade dolomite marble along the fault zone. The dolomite marble or tongue left at the top of the rock mass contacts with magmatic intrusion and hydrothermal solution to form diopsidation, olivization and tremolite alteration, which is one of the material conditions for the formation of jade.
4. Contact metasomatism occurred again when the hypabyssal intermediate-acid dikes originated from the late Variscan intrusive body invaded the alteration zone of dolomite marble in the jade-forming period. Under suitable geological conditions (300? Jade was formed at 350 degrees Celsius, 2.5 kPa and a certain torsional and compressive stress).
Time required for formation:
In fact, jade is a particularly hard ore. Judging from the chemical composition, it is pyroxene. Jade was formed more than1.300 million years ago, which is equivalent to the late Jurassic. The formation of jade, like the formation of various rocks, is the product of natural changes, and beautiful jade has become a gem because of its scarce output.
Classification of jade: category
The people who worship jade in the world, whether Maya, Eskimo, Inca or Maori in New Zealand in America, are not as good as the Chinese people in the long history of jade management, colorful jade varieties and meticulous use of jade. The traditional jade materials in China are mostly amphibole and pyroxene. Also known as nephrite and jadeite.
Shetaicui, Inner Mongolia
She Taicui was formed in the submarine siliceous deposit 65.438+0.80-240 million years ago. After many geological tectonic movements and the infiltration of hydrothermal solution containing chromium, quartzite with chromium as the main component has been formed, which is light green to white, translucent, hard and dense, delicate and moist after polishing, bright in color and pleasing to the eye.
1. Mohs hardness 7. 1.
2. Density: 2.6
3. Refractive index: 1.54
4. Radioactivity 3-5R (safety standard is 40R)
5. Optical properties: transparent? translucence
6. Color: light green and white
7. Acid and alkali corrosion resistance
1. color: jade experts attach great importance to color. Color is not only an important criterion for evaluating the quality of jade, but also the main basis for classifying jade types. The color of She Taicui is not the best among all kinds of jade, but its unique rich color is also cherished.
Compared with jadeite in other areas at home and abroad, she Taicui has more colors and forms her own series. She Taicui has three basic colors: white, cyan and emerald, and some transitional colors, such as bluish white, grayish white, bean green and dark green. According to industry legend, the white jade in She Taicui is said to match the field, and the quality of jade is said to be inferior to that of jade, which is extremely precious and high-grade jade.
2. Hardness: Hardness is one of the important signs to identify She Taicui. The hardness of minerals is a mechanical property of minerals to resist the invasion of other objects. There are usually two kinds of hardness:
(1) relative hardness, or Mohs hardness, is a kind of scratch hardness.
(2) Absolute hardness, also called indentation hardness. According to the weight that the mineral surface can bear. The Mohs hardness of Shetaicui is between 6.9 and 7.2, with slight differences among different varieties. Generally speaking, the hardness of white jade is slightly greater than that of jadeite. In the jewelry industry, hardness is generally regarded as an important symbol to distinguish gems from jade. The hardness of gemstones is generally above 7.3 degrees Mohs, and the hardness of jade is generally between 4 and 7.2 degrees Mohs. She Taicui has high hardness, good grindability and easy preservation, and has certain collection value.
3. Density: Density is the weight of jadeite per unit volume. She Taicui's weight measured with a small weight sample is 2.65 ~ 2.85. Different varieties are slightly different, white jade 2.85, blue white jade 2.65 and jadeite 2.75.
4. Transparency: Transparency is the degree to which jade allows visible light to pass, which is mainly related to the absorption of light by jade. Mineralogy can generally be divided into four types: transparent, translucent, micro-transparent body and opaque. She Taicui belongs to micro-transparent body, which can transmit light under the general enterprising degree, but can't see the transparent objects clearly.
5. Gloss: Gloss is the ability of jade to reflect light. Her brittle luster belongs to glass luster. This luster is neither strong nor light, that is, there is no crystal inspiration of strong light, nor wax texture of weak light, and it is soft, delicate and shiny.
Xinjiang khotan jade
Hetian jade is composed of amphibole actinolite. It is the main source of ancient jade in China. Produced in the foothills and riverbeds of Kunlun Mountain. Mainly in Hotan area. Its jade is hard and delicate. The mineral produced in the mountains is mountain jade, and the mineral produced in the river bed is seed material. According to the color, it is divided into: white jade, topaz, jasper, jet, sapphire, sugar jade and so on. The first-class white jade is pure and flawless, and is called suet jade. Other people with pure and flawless colors are hard to find and expensive.
Daqianyu
Daqian Jade, also known as Tuojiang Daqian Jade, Changhong Jade, Tuojiang Jade, Daqian Seed Jade, Tuojiang Shuiyu, Tuojiang Cai Yu and Yangtze River Sister Jade, is the Tuo of Sichuan.
The general name of all kinds of seed jade produced in river basins. Because the Tuojiang River originated in Jiuding Mountain, Maoxian County, Sichuan Province, with many tributaries and great changes. The jade materials produced are varied and colorful; In addition, the main stream of Tuojiang River passes through Zizhou (now Ziyang area in Sichuan and Neijiang area in Sichuan), the exile place of Changhong, a famous minister in the Eastern Zhou Dynasty, and Neijiang city in Sichuan, the hometown of Zhang Daqian, a famous master of Chinese painting, so the jade materials produced by Tuojiang River are honored as Changhong Jade and Daqianyu by jade players. There are many kinds of jade materials in Tuojiang River, mainly because the source of Tuojiang River is complex and there are many tributaries. Unlike other rivers, Tuojiang River is a mixed-race river. In addition to some tremolite jade in Longxi Township, Wenchuan County, Sichuan Province, various seed jade materials produced by other tributaries also rushed into Tuojiang River with geological changes. After tens of thousands of years of panning, only one kind of high-quality seed jade remains, and some high-quality seed jade is moist and transparent. Moreover, the total length of Tuojiang River is about 7 12km, which is a first-class tributary of the Yangtze River. Therefore, Tuojiang Daqian Jade is also called Yangtze Jade Sister Jade.
According to the testing standards of China People's * * and China National Jewelry and Jade Name (GB/T 16552) and Jewelry and Jade Identification (GB/T 16553), the jade materials produced in Tuojiang River meet the national testing standards of natural jade in terms of chemical composition, physical characteristics (hardness, internal crystal state and optical color characteristics), and pass the test.
In addition, because Daqian jade in Tuojiang is the essence of jade after long-term river scouring and soil and water nourishment, its value is 5 to 15 times higher than that of Shanyu mine, and some seed jade skins are usually left during processing to show its seed jade identity. [3]
Xiushanyu
Produced in Xiuyan County, Liaoning Province, named after it. The main component is bean green fiber serpentine, which is soft in texture and low in hardness. A variety of colors: light green, light yellow, fruit green, translucent or not transparent body, with a fatty luster on the surface. It is a jade material distributed and used earlier in China, and it is the largest jade material today because of its large output.
Serpentine jade species also include Jiuquan jade in the mountainous area near Jiuquan, Gansu Province, which is translucent green with black enamel. Famous? Glowing cup? There are not only Jiuquan jade, but also Yixin jade in Guangdong, Baihua jade in Fangshan, Kunlun jade in Kunlun Mountain and Taiwan jade in Taiwan Province Province. Most of them belong to the green system.
Nanyangyu
Also known as dushan jade. It is a kind of jade with complex composition and many minerals. It's hard and delicate. Its main components are plagioclase, zoisite, epidote, amphibole and diopside. Based on green, purple and white, it often presents various colors. Jade workers carve different objects according to natural colors, which is suitable for? Is it beautiful? Technology. Nanyang fish has a long history of development and utilization.
lantian jade
Lantian is produced in Lantian County, Xi City, Shaanxi Province, and has been famous for producing jade since ancient times. Did the Tang people have it? Blue fields are breathing their jade to the sun? This poem. Later, because the old mine dried up, mining stopped. At present, the jade mined in Lantian is serpentine diopside, opaque, yellow-green, dark green and emerald green.
Yuxianyu
Produced in Xizhuquan Temple in Xinmi, Henan Province. It is a sedimentary metamorphic quartzite. Low hardness. Colors are green, crimson, white, yellow and so on. Typical dense jadeite shows black spots in dense blue. The polished surface has a glass-like luster.
Jingbaiyu
Produced in Mentougou, Beijing, it is a white dense quartzite. The structure of fiber interweaving is different from other jade materials. But a granular structure. Its nature is fragile. The polished surface looks like suet jade.
turquoise
In the Neolithic Age, it was used as an ornament together with jade such as sapphire and agate. Jingzhou stone? Or? Xiangyang dianzi? Known as. Turquoise is an oxide cryptocrystalline lump or nodule of copper, with different shades of blue and green, often containing iron wire, hardness of 5-6, and waxy luster. Hubei produces high quality turquoise, which is famous at home and abroad. Turquoise in China has been found in Shaanxi, Xinjiang, Anhui, Henan and other provinces in recent years, except the famous northwest Hubei. Because all counties in northwest Hubei were under the jurisdiction of Xiangyang Road in ancient times, the turquoise produced in counties in northwest Hubei is called Xiangyang Dianzi, and its mining history is relatively long. But Persia is the most famous turquoise producing area in the world, because it was imported to European countries through Turkey. Turkish jade? Or? Turkic jade? Known as.
Jade Hongshan
In Hongshan Culture Circle of Inner Mongolia, the best jade mine was found in the hometown of China Yilong. North latitude: 42? 1 1? 23? ; East longitude: 1 19? 5 1? 59? . Coordinate of inflection point: x: 4676900y: 20736700. It is 825m above sea level, with a vein length of1600m, a width of1.5m, a depth of more than 80m (estimated depth is about 500m), and a prospective reserve of1000-800,000 cubic meters (if the cheap jade material1000 yuan/kg, it is. It is large, delicate, moist, diverse in color, unique and rich in materials, very similar to Hetian jade in color and moisture, and also like Shoushan stone. Comprehensive analysis shows that this material is second only to Hetian jade, but better than mid-range Hetian jade, and also better than Qinghai White, dushan jade, lantian jade and Xiuyu jade. The composition is close to chalcedony, but it is not glass luster, but belongs to jade luster, so it is a new jade material. This vein belongs to the timely vein and is a relatively stable vein in geology. It is very likely that there will be a huge jade king material in the mining process.
Purple chalcedony
Amethyst mine was first discovered in China after Amethyst mine in Arizona, USA, and its color is very purple, much higher than Amethyst. You can make high-end jewelry sets. The vein is about half a meter wide and more than 80 meters deep. It should be the largest and most valuable vein in the gem mine.
Sheep fat white jade
It is a gem-grade material in Hetian jade and the best in white jade. It has the best luster and texture, and its characteristics are: moist, dense, pure, white and flawless, like congealing fat, hence the name. The easiest way to distinguish this kind of jade from ordinary white jade is to watch it under white fluorescent lamp. Facing the fluorescent lamp, the suet white jade is white and transparent, and it has a feeling of powder fog. The general white jade, although translucent to the fluorescent lamp, has no sense of powder fog. The biggest difference between the two is that white jade is visible to the naked eye regardless of its grade, but there must be different shades of light yellow under the white fluorescent lamp, so if there is a trace of light yellow under the fluorescent lamp, it cannot be called suet white jade. The rare suet jade that meets the harsh standards is definitely a gem that can't hold any impurities.