20 18, 18 February, a yellow diamond weighing 552 carats was unearthed in Canada, becoming the largest diamond found in North America.
Chinese name: diamond English name: diamond alias: Jin Gangzuan chemical formula: C molecular weight: 12.0 107(8) CAS registration number: 7782-40-3 EINECS registration number: 23 1-953-2 Absolute hardness:/kloc-2. 00 physical property data, computational chemical data, physical properties, hardness, color, chemical properties, structural properties, optical properties, stability, diamond and graphite, synthetic diamond, main origin, use, industrial use, chronic poisoning, ornamental gems, physical property data 1. Properties: Powder 2. Density (g/ml at 25℃): 3. C): 3550 C-4000 C 4。 Absolute hardness: 10000-2500 calculated chemical data: 1, calculated hydrophobic parameter reference value (XLOGP):- 1. 1.2, number of hydrogen bond donors: 0.3, number of hydrogen bond receptors. Topological molecular polar surface area (TPSA): 34. 1.7, heavy atom number: 2.8, surface charge: 0.9, complexity: 0. 1, isotope atom number: 0. 1, confirmed atom solid center number: 0.1. The determined number of chemical bond stereocenters is 0 14, the uncertain number of chemical bond stereocenters is 0 15, and the number of * * valence bond units is 1. Physical properties hardness Mohs hardness 10, new Mohs hardness 15, microhardness 10000kg/mm 2. The hardness of diamond is directional. The hardness of octahedral crystal face is greater than that of rhombohedral crystal face, and the hardness of rhombohedral crystal face is greater than that of hexahedral crystal face. According to Mohs hardness scale, it is divided into 10 grade, with diamond as the highest grade and 10 grade. For example, the hardness of knives is about 5.5, copper coins are about 3.5 to 4, nails are about 2 to 3, and the hardness of glass is 6. Because of the highest hardness, diamond powder or laser (such as 532nm or 1064nm wavelength laser) must be used for diamond cutting. The density of diamond is 3.52 g/cm, the refractive index is 2.4 17 (at 500 nm) and the dispersion rate is 0.044. Colored diamonds come in various colors, ranging from colorless to black, with colorless being particularly preferred. They can be transparent, translucent or opaque. Many diamonds are yellow, mainly because they contain impurities. Diamonds have very high refractive index and strong dispersion, which is also the reason why diamonds reflect colorful flashes. Diamonds emit blue-green fluorescence under X-ray irradiation. Primary diamond ore only occurs in kimberlite cone or a small amount of K-Mg lamprophyre. Kimberlite is their parent rock, and diamonds from other places are transported by rivers and glaciers. Diamonds are generally granular. If the diamond is heated to 1000℃, it will gradually become graphite. China also has the technology to make diamonds, but the maximum is only about 0.2 carats. According to GIG's report, the chemical composition of diamond is C, which is a homogeneous polymorph of carbon and graphite. In the chemical composition of minerals, there are always elements such as silicon, magnesium, aluminum, calcium, manganese and nickel. And common impurity elements such as sodium, boron, copper, iron, cobalt, chromium, titanium, nitrogen and carbohydrates. The crystal structure of diamond minerals belongs to equiaxed tetrahedron structure and has the same polar bond. Carbon atoms are located at the top and center of tetrahedron and have high symmetry. The carbon atoms in the unit cell are connected by homopolar bonds with a distance of 154pm. The common crystal forms are octahedron, rhombic dodecahedron, cube, tetrahedron and hexahedron. The absolute hardness of diamond is four times that of corundum and eight times that of corundum. The detailed absolute hardness is as follows: diamond 10000-2500 corundum 2500-2 100 time 1550- 1200. Minerals are brittle, shell-like or hackly fracture, and will crack along the crystal cleavage plane under small impact, with medium or perfect cleavage parallel to octahedron and perfect cleavage parallel to dodecahedron. The minerals are relatively pure, and the density is generally 3470-3560kg/m3. The color of diamond depends on the purity, the type and content of impurity elements. Ultra-pure diamonds are colorless and usually have different degrees of yellow, brown, gray, green, blue, ivory and purple. Pure people are transparent, translucent or opaque, with impurities; Under cathode ray, X ray and ultraviolet ray, it will emit different colors of fluorescence such as green, sky blue, purple and yellow-green. Light blue phosphorescence is emitted in the darkroom after the sunlight is irradiated; Diamond luster, a little greasy or metallic luster, high refractive index, generally 2.40-2.48. Chemical diamond is a kind of simple crystal composed of carbon element formed in the deep part of the earth at high pressure and high temperature, which refers to polished diamond. Diamond is a colorless octahedral crystal, which is composed of pure carbon and carbon atoms connected by tetravalent bonds. It is the hardest substance known to exist naturally at present. Because the C-C bond in diamond is very strong, all valence electrons participate in the formation of valence bond, and there are no free electrons, so the hardness of diamond is very high, the melting point is 6900 degrees Fahrenheit, the ignition point of diamond in pure oxygen is 720 ~ 800 degrees Celsius, and in air it is 850 ~ 1000 degrees Celsius, which is non-conductive. Structural characteristics Diamond structure can be divided into: equiaxed tetrahedral cube and hexagonal diamond. In diamond crystal, carbon atoms are interconnected by tetrahedral bonds, forming an infinite three-dimensional skeleton, which is a typical atomic crystal. Each carbon atom forms a valence bond with the other four carbon atoms through SP3 hybrid orbitals, forming a regular tetrahedron. Because the C-C bond in diamond is very strong, all valence electrons participate in the formation of valence bond, and there are no free electrons, so diamond is not only hard, but also has a very high melting point and is not conductive. In industry, diamonds are mainly used to make probes and abrasives for drilling, and also used to make high-grade decorations such as hand ornaments with complete shapes, which are very expensive. The Mohs hardness of diamond is10; Because the hardness of natural substances is the highest, diamond powder must be used in diamond cutting. The density of diamond is 3.52g/cm3, the refractive index is 2.4 17, and the dispersion rate is 0.044. Optical Brightness (1) diamond has very high reflectivity, its critical angle of reflection is small, its total reflection range is wide, light is prone to total reflection, and the amount of reflected light is large, thus producing very high brightness. (2) The flashing of the flashing diamond is flashing, that is, when the diamond or light source moves relative to the observer, the surface reflects and flashes white light. Colorless, transparent and well-crystallized octahedral or curved diamonds can show good scintillation even without cutting and grinding. (3) The crystal faces of dispersion or fire diamonds are like a prism, which can decompose the white light entering the crystal through refraction, reflection and total reflection into the constituent colors of white light-red, orange, yellow, green, blue, indigo and purple. (4) The crystal plane or cleavage plane with luster as hard, flat and bright as a diamond has a particularly strong reflection effect on white light, which is called diamond luster. Stable diamond has stable chemical properties, acid resistance and alkali resistance, and does not react with concentrated HF, HCl and HNO 3 at high temperature. Only in the melt of Na 2 CO 3, NaNO 3 and KNO 3, or when it is boiled with the mixture of K 2 Cr 2 O 7 and H 2 SO 4, the surface will be slightly oxidized. Corrosion in high temperature gases of o, CO, CO 2, h, Cl, H 2 O and CH 4. Diamond also has non-magnetism, poor conductivity, oleophilic hydrophobicity and triboelectricity. Only Ⅱ B diamond has good semiconductor properties. According to the difference of nitrogen impurity content and thermal, electrical and optical properties of diamonds, diamonds can be divided into two categories: type I and type II, and further subdivided into four subcategories: 1a, 1b, 2a and 2b. Type Ⅰ diamond, especially subtype Ⅰ A, is a common common diamond, accounting for about 98% of the total natural diamonds. Type I diamonds contain a certain amount of nitrogen, which has good thermal conductivity, poor electrical conductivity and good crystal shape. Type ⅱ diamond is extremely rare, with little or no nitrogen content, and has the characteristics of good thermal conductivity and crystal bending. Diamonds of type Ⅱ b are semiconductors. Second-class diamonds are mostly used in aerospace technology and cutting-edge industries because of their excellent properties. The world's largest industrial diamonds and gem-grade diamonds both exceed 365,438+000 carats (65,438+0 carats = 200mg). Among them, the gem-grade diamond with the size of 10× 6.5× 5cm was named "Cullinan" and was discovered in Premil Rock Tube in 1905. China Changlin diamond, weighing 158.786 carats, was discovered by Wei Yu 1977, a female member of Changlin Brigade in Linshu County, Shandong Province, and was later listed as a world-famous diamond. The main diamond producing areas in the world are South Africa, Australia, Botswana and Russia. Diamond and graphite both belong to elemental carbon, and their chemical properties are completely the same, but diamond and graphite are not the same substance, they are allotropes composed of the same elements. The difference is the physical structure characteristics. The chemical formula of both of them is C, and the regular hexagon formed between graphite atoms is planar and flaky. Diamond atoms have a three-dimensional regular tetrahedron structure. Comparison of melting points between diamond and graphite: the melting point of diamond is 3550℃, and that of graphite is 3652℃ ~ 3697℃ (sublimation). The melting point of graphite is higher than that of diamond. From the inside of the sheet, graphite is an atomic crystal; From the perspective of lamellar crystals, graphite is a molecular crystal (generally speaking, graphite should be a mixed crystal); Diamond is an atomic crystal. It seems incredible that the melting point of graphite crystal is higher than that of diamond, but the valence bond length in graphite crystal lamellae is1.42×10-10m, and that in diamond crystal is1.55×10-. Both of them are * * * valence bonds. The smaller the bond length, the greater the bond energy, the stronger the bond, the more difficult it is to break, and more energy needs to be provided, so the melting point is higher. (Mainly due to the atomic crystal properties of graphite, its melting point is high. There are two main methods for synthetic diamond: high temperature and high pressure method and chemical vapor deposition method. The technology of high temperature and high pressure method is very mature and has formed an industry. The domestic output is extremely high, ranking first in the world. Chemical vapor deposition still mainly exists in the laboratory. Kimberly diamond mine was discovered by bernat Brothers in 1870. It is this discovery that makes people know what kind of rocks may contain diamonds. It turned out to be a volcanic rock formed after magma cooled in ancient times. Then, the researchers found that in addition to diamonds, this volcanic rock also contains two minerals called garnet and olivine. Therefore, in those places where garnet and olivine are produced, it is relatively possible to find diamond mines. Therefore, garnet and olivine have become "indicator minerals" for finding diamonds. The method of finding diamond mines according to indicator minerals was not suddenly discovered one day. In 1970s, John Gianni, a geochemist of Smithsonian Institution, published his research results after carefully studying the relationship between garnet and diamond. However, before that, that is, in the 1950s, geologists of De Beers Company had been searching for diamond mines all over the world according to indicator minerals. Diamond mines have been discovered all over the world. Among them, Australia, Congo, Russia, Botswana and South Africa are five famous diamond producing areas. Dr Steven Hagarty, a geophysicist at the University of Massachusetts in the United States, studied the age of 1999 lava containing diamonds around the world and found that these lava containing diamonds were formed by magma ejected from various places in at least seven different periods in the past. The oldest lava was formed about 10 billion years ago. In these seven magmatic eruptions, Africa and Brazil ejected the most diamonds from 654.38+0.2 billion years ago to 80 million years ago. It was the Mesozoic Cretaceous in the heyday of the dinosaur era. Lava containing diamonds was formed by magma ejected 22 million years ago at the latest. As for whether the lava formed later contains diamonds, it is still uncertain. In the more than 20 years since 197 1, several diamonds over 50 carats and over 100 carats have been found in China. The time sequence of discovery is as follows:1.191.9.25 A diamond weighing 52.50555555555562.197765438+2.26555 was named "Chang Lin Diamond" 3./kloc-. It was named "Chenbu 1". 4. 1982 In September, a 96.94-carat diamond was found in Chenbu, Tancheng, Shandong Province. 5./kloc-0 In May, 983, a 92.86-carat diamond was found in Chenbu, Tancheng, Shandong Province. 6.1983165438+1October 14 A giant diamond named "Mengshan No.1" was found in Mengyin, Shandong Province. Mengyin diamond mine is the largest primary mine in China. According to the data of 1987, the main diamond metallogenic areas in China are: ① Liaodong-Jinan metallogenic area, with kimberlite in Mesozoic and Mesozoic. (2) Western Shandong, northern Jiangsu and northern Anhui are metallogenic areas, and there may be multi-stage kimberlites in the Lower Paleozoic. ③ Kimberlite is found in Taihang Mountain, Songshan Mountain and Wutai Mountain in Shanxi, Henan and Hebei mining areas. ④ Hunan, Guizhou, Hubei and Sichuan metallogenic areas, and four diamond placers with industrial value were found in Shui Yuan Valley, Hunan Province. Hunan diamonds are produced in Dingjiagang, Taoyuan and Qianyang in Changde, Hunan. Hunan diamonds are mainly placers, mainly distributed in Yuanshui River Basin, with scattered distribution and low grade, but good quality, with gem-grade diamonds accounting for about 40%. According to legend, during the Ming Dynasty, sporadic diamond discoveries were made in Yuanjiang Valley, Hunan Province, and large-scale prospecting began in the 1950s. Diamonds are distributed in all waters of Yuanjiang River, but only Dingjiagang in Changde, Chexichong in Taoyuan County, Xinzhuanglong in Xupu County (Qianyang) and Yaotou in Yuanling County are of mining value. Diamonds in Hunan have different shades, with obvious differences inside and outside, and are distributed in strips and spots. Its brown series diamond crystals are yellow-brown, with clean interior and a large number of brown spots on the surface. Brown spots are yellow, tan, brown, black and so on. , mainly distributed on the corroded surface of diamond. Brown is mainly caused by the radiation of radioactive particles in nature. The overall particle size of diamond is small, but the texture is good, mainly single crystal, accounting for about 98% of the total output; The crystals are relatively complete, mainly octahedron, dodecahedron and hexahedron; Most crystals are light transparent or yellow, brown, etc. The grain weight is less than 28mg, generally10.9 ~15 mg; 22% crystals contain inclusions; There are cracks on the surface of 60% crystals, and the surface dissolution is not heavy. 20 18, 18 February, a yellow diamond weighing 552 carats was unearthed in Canada, becoming the largest diamond found in North America. The American media reported on June 5438+05 that this diamond was 33.74 mm long and 54.56 mm wide. It was discovered by Dominion Diamond Mines in Diavik Diavik Diamond Mines in northwest Canada in June 5438+00. Use industrial geological drill and petroleum diamond, diamond for wire drawing die, diamond for abrasive, diamond for dresser, diamond for glass cutting machine, diamond for hardness tester head and diamond for handicrafts. If coated on the audio paper basin, the sound quality of the speaker will be greatly improved. Chronic Poison During the Renaissance, chronic poison made of diamond powder was popular among Italian giants. People who eat diamond powder will stick to the stomach wall. In the long-term friction, it will cause gastric ulcer, and if it is not treated in time, it will die of gastric bleeding. It is a chronic poison that is difficult to prevent. Ornamental gems and diamonds have become ladies' favorite gems because of their high refractive index. Huge beautiful diamonds may be priceless. Diamonds with dark colors are more expensive. At present, the most expensive colored diamond is aquamarine diamond with a slight blue color. Diamonds are divided into type I and type II, mainly depending on whether they contain N elements: type I contains N elements; Type II does not include. The blue diamond is type B, which is a semiconductor.