All diamonds are formed under the conditions of high temperature and high pressure deep in the earth's crust and brought to the surface by volcanic eruption.
Diamonds are formed underground 160-480 km. Most diamonds are found in a volcanic rock called kimberlite, which is buried in areas where volcanic activity is still active. Any other directly discovered diamond is directly separated from the original kimberlite by other actions.
There are 20 countries producing diamonds in the world. South Africa is the fifth largest diamond producer, and the top four are Australia, Democratic Republic of Congo, Botswana and Russia.
Diamonds are made of pure carbon, so is graphite. Lead in pencils is made of graphite. However, the atomic internal arrangement of diamond and graphite is different. Diamond is one of the hardest substances naturally existing on the earth, and its Mohs hardness is 10. Graphite is one of the softest substances naturally existing on the earth, and its Mohs hardness is 1.5, which is only a little harder than talcum powder.
Question 2: How are diamonds formed? 65,438+00. From the experiment of high temperature and high pressure, it is known that octahedral diamond with coarse particles and transparent and colorless can be formed at high temperature, especially at high pressure. If the pressure is stable and the temperature drops rapidly, the diamond is still in a stable state; On the contrary, if the temperature is stable and the pressure drops rapidly, it will easily lead to dislocation slip of diamond crystal structure, induce lattice defects, turn some colorless diamonds into brownish yellow and brownish yellow, and gradually graphitize diamonds. Therefore, the primary condition of diamond formation is colorless and transparent diamond formed at high temperature and high pressure, and the pressure should remain basically unchanged or slowly decrease during the rising process. But in the open system of the earth, especially near the surface, the pressure will drop rapidly. In order to keep the temperature and pressure constant during the magma rising, the magma must rise rapidly first. The kimberlite magma containing diamonds can rise at a speed of 70 km/ h and reach the surface in a few hours, which just meets the above requirements. In addition, the formation of diamonds is closely related to its formation mode and environment.
Question 3: How are synthetic diamonds formed? Primary diamond crystallizes in the deep underground (130- 180 km) at high temperature (900- 1300℃) and high pressure (45-60) × 108 Pa. They are stored in kimberlite or eclogite. South Africa's Kimberley mine, peridotite diamonds were formed about 3.3 billion years ago, almost the same age as the earth; The ages of Australian argyle mine, Botswana Olab mine and eclogite diamond are 65.438 0.58 billion years and 990 million years respectively. The diamond crystal hidden in such a large underground depth for hundreds of millions of years will have to help the volcano erupt, and the lava flow will bring the magma containing diamonds to the earth's near surface or migrate to the river sand for a long time. The former forms primary tubular ore and the latter forms alluvial ore. After hard mining, these ore bodies need multiple treatments to get strange original stones from them. Only about 20% of rough diamonds can be used as rough diamonds for jewelry, and most of them can only be used for industrial purposes such as cutting, grinding and polishing. It is roughly estimated that at least 250 tons of ore must be mined and processed to obtain diamonds weighing 1ct, and the recovery rate is quite low. If you want to choose beautiful diamonds from finished diamonds, the ratio between them is even more disparity. ?
It is known that only more than 30 countries and regions in the world produce diamonds, and their distribution is extremely uneven, mainly in Australia and Africa, followed by Asia and South America. Among them, Australia, Zaire, Botswana, the former Soviet Union and South Africa are the five largest diamond producers in the world, accounting for more than 80% of the global rough diamond supply.
Although China has a long history of mining and development, diamonds have been found in Taoyuan, Changde and Tancheng in the Qing Dynasty. In the middle of 20th century, diamond placer was also discovered in Hunan. The primary diamond deposits were only found in Wafangdian, Liaoning, Mengyin, Shandong and eastern Guizhou in the 1960s and 1970s. ?
Rare things are expensive. Looking at the world today, diamonds are less distributed and the output is low. Coupled with the difficulty of mining, natural diamonds are even more precious. A diamond, from being bred in the magma of the earth's crust to being worn on the hand, traveled all over Wan Li and passed through the hands of hundreds of people. Mining and processing are difficult and complicated, and making exquisite ornaments is an artistic creation. Finally, after you learn and wear it, show it off in front of the world again. Therefore, what a strange fate!
What is a synthetic diamond?
Diamonds are nobles in jewelry, which are polished by diamond processing. Bright and transparent, it exudes a noble brilliance of Leng Yan, and it has the temperament of "getting out of the mud without being stained". The formation and discovery of natural diamonds are extremely difficult. It is formed under the special conditions of high temperature and high pressure in the deep part of the earth after hundreds of millions of years of "penance". Due to the crustal movement, they came to the surface from the deep part of the earth and were hidden in kimberlite, thus being discovered and mined by human beings.
Diamonds can not only be processed into priceless jewelry, but also have great potential in industry. High hardness and good wear resistance, and can be widely used in cutting, grinding and drilling. Because of its high thermal conductivity and good electrical insulation, it can be used as a heat dissipation plate for semiconductor devices; It has excellent light transmittance and corrosion resistance, and is also widely used in the electronic industry. At the end of 18, it was discovered that expensive diamonds were originally allotropes of carbon. Since then, the preparation of synthetic diamond has become the glory and dream of many scientists.
A century later, another simple form of carbon, graphite, was discovered, and people tried to simulate the natural process to transform graphite into diamond under the environment of ultra-high temperature and high pressure. In order to shorten the reaction time, special conditions of 2 000℃ and 55 000 atmospheric pressure are needed.
1955, General Electric Company of the United States specially manufactured high-temperature and high-voltage electrostatic equipment, obtained the first batch of small industrial synthetic diamond crystals in the world, and initiated the industrial scale production of synthetic diamond abrasives. Now their annual output is about 20 tons. Soon, DuPont invented the explosion method, using the high pressure and rapid temperature rise generated by the instantaneous explosion, and also obtained artificial diamonds with a size of several millimeters.
The performance of diamond film is slightly inferior to that of diamond particles, and its density and hardness are lower. Even so, its wear resistance is one of the best, and the life of a film only 5 microns thick is more than 10 times longer than that of hard alloy steel. We know that the stylus of a record has to bear great pressure on the tiny contact surface, and at the same time it requires extremely long wear-resistant life. As long as a diamond film is deposited on the needle tip, it can easily go into battle. If diamond film is used as wear-resistant coating on plastic and glass, its application can be greatly expanded. & gt
Question 4: How are diamonds formed? Diamonds are the hardest and simplest gems in the world. It is a cubic natural crystal composed of carbon. Its composition is basically the same as our common coal, pencil lead and sugar. Under high temperature and pressure, carbon element crystallizes to form graphite (black), while under high temperature, extremely high pressure and reducing environment (usually anoxic environment), it crystallizes to become precious diamond (colorless). In order to understand the origin of diamonds, first look at the original rocks containing diamonds. Since the discovery of diamonds in India, we have been hearing stories about people finding diamonds on rivers and beaches. This is because the original rock containing diamonds located in the upper reaches of the river is weathered and broken, and the diamonds are taken downstream with the water flow, and the heavier diamonds are buried in the gravel. What is the original stone of a diamond? 1870, diamonds were dug up in the loess of a farm in South Africa. After that, the excavation of diamonds moved from the river bed to the loess. Below the loess is a hard dark blue rock, which is the original stone of diamonds-kimberlite. What is kimberlite? Kimberlite is an alkaline ultrabasic volcanic rock, which is formed in the deep part of the earth and contains a lot of volatile components such as carbonic acid gas. This kind of rocks often contain peridotite and eclogite fragments from the deep earth, and the main mineral components are olivine, phlogopite, carbonate, pyroxene and garnet. The study shows that kimberlite magma was formed in the deep part of the earth below 150 km. Because this rock was first discovered in Kimberly, South Africa, it was named after this place name. Another kind of original rock containing diamonds is called K-Mg lamprophyre, which is an overbased magnesian volcanic rock. It is mainly formed by leucite and volcanic glass, and may contain minerals such as pyroxene and olivine. Its typical origin is argyle, Western Australia. Through the study of diamonds and their primary inclusion minerals from different mines in the world, scientists found that the formation conditions of diamonds are generally 4.5-6.0Gpa (equivalent to 150-200km depth) and1100-1500℃. Although diamonds can be formed in various periods/stages of the earth's history in theory, most of the mines mined were mainly formed 3.3 billion years ago and12-1700 million years ago. For example, some diamonds in South Africa are about 4.5 billion years old, indicating that these diamonds began to crystallize in the deep part of the earth shortly after its birth. Diamonds are the oldest gems in the world. The formation of diamonds needs a long historical process, which can be confirmed by the fact that diamonds are mainly produced in the ancient and stable mainland areas of the earth. In addition, the impact of extraterrestrial stars on the earth can produce instantaneous high temperature and high pressure, and can also form diamonds. For example, the report of the former Soviet Academy of Sciences 1988 found diamonds in meteorites, but the diamonds formed by this action have no economic value. Rare diamonds are mainly produced in two kinds of rocks, one is peridotite and the other is eclogite, but only the former has economic significance. So far, there are two kinds of peridotite containing diamond: kimberlite (named after a place name in South Africa-kimberlite) and K-Mg lamprophyre, both of which are produced by volcanic eruption. Rocks formed in the deep part of the earth are brought to the surface or shallow part of the earth by volcanic activities. This magma is mostly produced in the form of rock tubes, so it is commonly called "tube ore" (primary ore). Kimberlite or kimberlite containing diamond is exposed on the surface and weathered and broken by external forces such as wind and rain. Under the scouring of water, the broken protoliths and diamonds are taken to the riverbed and even the coastal zone for reproduction, forming alluvial sand deposits (or secondary deposits).
Question 5: How did diamonds come from? Are they naturally formed? Well, it used to be a diamond, one of the hardest stones in the world. Its carbon structure is triangular and it was cut into diamonds.
Question 6: The formation principle of diamonds. Diamonds are the products of diamond finishing. Diamonds are the hardest and simplest gems in the world. It is a cubic natural crystal composed of carbon. Its composition is basically the same as our common coal, pencil lead and sugar. Under high temperature and pressure, carbon element crystallizes to form graphite (black), while under high temperature, extremely high pressure and reducing environment (usually anoxic environment), it crystallizes to become precious diamond (colorless). Since the discovery of diamonds in India, some people have found diamonds on rivers and beaches. This is because the original rock containing diamonds located in the upper reaches of the river is weathered and broken, and the diamonds are taken to the downstream zone with the water flow, and the heavier diamonds are buried in the gravel. 1870, diamonds were dug up in the loess of a farm in South Africa. After that, the excavation of diamonds moved from the river bed to the loess. Below the loess is a hard dark blue rock, which is the original stone of diamonds-kimberlite. Kimberlite is an alkaline ultrabasic volcanic rock, which is formed in the deep part of the earth and contains a lot of volatile components such as carbonic acid gas. This kind of rocks often contain peridotite and eclogite fragments from the deep earth, and the main mineral components are olivine, phlogopite, carbonate, pyroxene and garnet. The study shows that kimberlite magma was formed in the deep part of the earth below 150 km. Because this rock was first discovered in Kimberly, South Africa, it was named after this place name. Another kind of original rock containing diamonds is called K-Mg lamprophyre, which is an overbased magnesian volcanic rock. It is mainly formed by leucite and volcanic glass, and may contain minerals such as pyroxene and olivine. Its typical origin is argyle, Western Australia. Through the study of diamonds and their primary inclusion minerals from different mines in the world, scientists found that the formation conditions of diamonds are generally 4.5-6.0Gpa (equivalent to 150-200km depth) and1100-1500℃. Although diamonds can be formed in various periods/stages of the earth's history in theory, most of the mines mined were mainly formed 3.3 billion years ago and12-1700 million years ago. For example, some diamonds in South Africa are about 4.5 billion years old, indicating that these diamonds began to crystallize in the deep part of the earth shortly after its birth. Diamonds are the oldest gems in the world. The formation of diamonds needs a long historical process, which can be confirmed by the fact that diamonds are mainly produced in the ancient and stable mainland areas of the earth. In addition, the impact of extraterrestrial stars on the earth can produce instantaneous high temperature and high pressure, and can also form diamonds. For example, the report of the former Soviet Academy of Sciences 1988 found diamonds in meteorites, but the diamonds formed by this action have no economic value.
Question 7: How are diamonds formed? Diamonds are formed by geological processes.
In ancient geological history, carbon was dissolved in magma deep in the mantle. When the external conditions such as temperature and pressure change, the carbon concentration reaches saturation level and begins to precipitate and crystallize into diamond blanks.
In the later stage of volcanic activity, the crystallized diamond rough was captured by kimberlite magma or lamprophyre magma, brought to the surface, and wrapped in kimberlite and lamprophyre to form primary ore. After weathering and denudation, the primary ore is brought to the river or coastal environment for deposition, forming secondary placer.
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Question 8: How are diamonds formed? Diamonds are carved from diamonds. Diamonds are a kind of mineral made of carbon, which is the hardest substance among many natural beings found on the earth at present. The absolute hardness of diamond is four times that of corundum and eight times that of corundum. Graphite can form synthetic diamond at high temperature and high pressure, and it is also a precious gem. Primary diamond is crystallized at high temperature and high pressure in the deep underground, and it takes a long time to form. Australia, Congo, Russia, Botswana and South Africa are five famous diamond producing areas.