diamond
Diamonds, also called diamonds, are commonly known as "Jin Gangzuan". The chemical formula is c, which belongs to carbon with graphite. It has excellent physical properties such as superhard, wear resistance, heat sensitivity, heat conductivity, semiconductor and penetration, and is known as the "king of hardness" and the king of gems. The crystal angle of a diamond is 54 degrees 44 minutes and 8 seconds. Traditionally, people often call processed products diamonds, while unprocessed products are called diamonds. In China, the name of diamond was first found in Buddhist scriptures. Diamonds are the hardest substance in nature. The best color is colorless, but there are also special colors, such as blue, purple and golden yellow. Diamonds of these colors are rare and precious among diamonds. India is the most famous diamond producer in history. Now many famous diamonds in the world, such as "Mountain of Light", "Regent" and "orlov", all come from India. The production of diamonds is very scarce. Usually, finished diamonds account for one billion of the mining, so the price is very expensive. Polished diamonds are usually round, rectangular, square, oval, heart-shaped, pear-shaped and olive-pointed. The heaviest diamond in the world is Cullinan, produced in South Africa in 1905 and weighing 3 106 carats. It is divided into nine small diamonds, among which Cullinan 1, known as the "Star of Africa", still ranks first among the world-famous diamonds.
Usage: 1: When people take diamond powder, it 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. During the Renaissance, chronic poison made of diamond powder was popular among Italian giants.
Crystal structure:
The unit cell is face-centered cubic structure, and each unit cell contains 2 groups of 8 C atoms.
A simple way to identify diamonds
With the increasing demand for jewelry and diamonds, the market for fake diamonds such as artificial diamonds is expanding, and even some jewelry operators can't tell the difference. Here are some simple ways to identify the authenticity of diamonds.
1, single refraction of diamond
The single refraction of diamond is determined by its essential characteristics. While other natural gemstones or artificial gem are mostly birefringent. When the fake diamond is observed with a magnifying glass of 10 times, it is easy to see that the edges and corners overlap, and two bottom lights are exposed at the same time from the slightly inclined front. If the difference in birefringence is small, such as zircon, you can also see the image of overlapping background light.
2. Adsorption of diamonds
Diamonds have a certain affinity for grease and dirt, that is, oil stains are easily adsorbed by diamonds. So touching the diamond with your fingers will feel sticky, and your fingers seem to feel sticky. This is not found in any gem. This method needs training to master the nuances.
3. Characteristics of straight lines
The surface of the diamond is polished very smoothly. Dip the pen in ink and cross the diamond. If it is a real diamond, the surface will leave a smooth and continuous line, which is characterized by a straight line. Forgery will leave dots and lines. Observation in this way should be made with the help of a magnifying glass.
4. Unique diamond luster
Under the incandescent light of 100 degree, it is easy to see which diamond has diamond luster by comparing with the counterfeit. This method should not be carried out in too dark or too strong light.
High hardness synthetic diamond
The R&D Center of General Electric Company of the United States has synthesized synthetic diamonds with atomic density per unit volume higher than that of any existing solid substance, and the hardness is higher than that of natural diamonds, which is the hardest material in the world. It contains 99% carbon 13 isotope and natural diamonds. According to scientists' observation, with the increase of carbon isotope density 13, the distance between atoms will be slightly reduced, which makes the hardness of artificial diamonds exceed that of natural diamonds with slightly loose atomic arrangement. In the process of synthesizing synthetic diamonds, scientists first precipitate carbon in methane gas rich in carbon isotope 13 into small diamond fragments by chemical evaporation, and then use very high pressure to decompose and recrystallize these small fragments into massive diamonds with a maximum weight of 3 carats.
Diamonds are usually yellow, brown, blue, green and pink, but colorless ones are more popular. There are 10 extra-large gem-grade diamonds weighing more than 620 carats (124 grams) in the world, among which the largest Cullinan weighs 3 106 carats (62 1.35 grams) and has a size of 5×6.5×65438. China Changlin diamond, weighing 158.786 carats, was discovered in Linshu county, Shandong province on 1977 and is listed as a world-famous diamond. The main diamond producing areas in the world are Australia, Zaire, Botswana, the former Soviet Union, South Africa, Brazil, Namibia, Ghana, Central Africa, Sierra Leone and China.
It is the tenth hardness grade of Mohs mineral.
Attachment: Giant diamonds and big diamonds produced in China.
In the twenty years since 197 1, several diamonds over 50 carats and over 100 carats have been discovered in China. The order of discovery time is as follows:
[1]1971On September 25th, a diamond weighing 52.7 1 carat was found beside Suqian Highway in Jiangsu Province.
[2] 1 97765438+February 2 1 day, in Changlin Brigade, Linshu County, Shandong Province, female player Wei found a high-quality giant diamond of1weight 158.786 carats, all transparent and yellowish in color, which can be called "the best in China". It was named "Chang Lin Diamond"
[3]1981August 5, 2005 124.27 carat giant diamond was found in Chenbu, Tancheng, Shandong. It was named "Chenbu 1".
[4] 1982 In September, a 96.94-carat diamond was found in Chenbu, Tancheng, Shandong Province.
[5] 1983 In May, a 92.86-carat diamond was discovered in Chenbu, Tancheng, Shandong Province.
[6]1983165438+1October 14 A giant diamond named "Mengshan No.1" was found in Mengyin, Shandong Province.
Diamond is polished diamond, also known as Jin Gangzuan, and the mineral name is diamond. English is Diamond, which comes from agonist in ancient Greece, meaning hard and inviolable substance.
① Usually refers to gem-grade diamonds, especially cut gem-grade diamonds. In fact, there is no such distinction between diamonds and diamonds abroad, and the same word "diamond" is used in English, but the word "diamond" is often used in the field of mineralogy and gemology in China. However, this is not entirely correct. For example, "industrial diamond" does not belong to the field of gemology, but people are used to calling it this way, so it is also used in this entry.
② Gemstone diamonds are colorless and transparent, but most of them are slightly yellow. The deeper the yellow tone or earthy tones, the lower the grade. There is a colorless and transparent one with a little blue inside, which is called "fire and water color", but it is a good product. Dark blue, dark black, deep gold, red and green are rare treasures, called "bright diamonds" or "rare diamonds". Diamonds in the same mining area have similar "pigment" characteristics, so that experienced people can often identify the origin of diamonds by this. The earliest invention of standard circular bright cutting was in 19 14, which was invented by a diamond cutter in Antwerp, Belgium. The criteria for judging diamonds are called 4C, which are clarity, color, cut and carat weight. Among them, clarity refers to the inclusions in diamonds and should not be called defects. The existence of inclusions just shows the naturalness of diamonds. Of course, we still hope that as few inclusions as possible, so there is a classification of cleanliness. Namely: LC, VVS, VS, SI, p level. In the past, people didn't ponder diamonds, but only used the original diamonds as ornaments. The time when diamond crystals really became diamonds and jewels was about 1450. At that time, diamonds had only 17 faces. The diamond ring worn by the Queen of England when she was in power from 1558 to 1603 was just an octahedral diamond crystal with a top worn off as a ring surface. Until 19 19, a Polish living in the United States named Tolkovsky designed 58 kinds of cutting techniques for turning diamonds, which are still in use today. This cut is accurately calculated according to the refractive index of the diamond and other factors, and cannot be changed at will, otherwise the polished diamond will lose its luster or leak light.
chemical composition
The chemical composition of diamonds is carbon, which is the only single element in gems. It belongs to the equiaxed crystal system. The crystal forms are mostly octahedron, rhombic dodecahedron, tetrahedron and their aggregates. Pure diamond is colorless and transparent, showing different colors due to the mixing of trace elements. Strong diamond luster. The refractive index is 2.4 17 and the dispersion is moderate, which is 0.044. An isotropic object. Thermal conductivity 0.35 calories/cm? Second degree. Tested by thermal conductivity meter, the response is the most sensitive. The hardness is 10, which is the hardest mineral known at present. The absolute hardness is 1000 times that of the time, and 150 times that of corundum. It is afraid of heavy blows, and it will be broken by cleavage after heavy blows. A set of cleavage is completed. The density is 3.52g/cm3. Diamonds are luminous, and after being irradiated by sunlight, they can emit light blue phosphorescence at night. X-ray irradiation emits sky blue fluorescence. The chemical properties of diamond are very stable, and it is not easy to dissolve in acid and alkali at room temperature, and acid and alkali will not affect it.
The difference between diamonds and similar precious stones and synthetic diamonds. Common substitutes or counterfeits in gem market include colorless gemstones, colorless spinel, cubic zirconia, strontium titanate, yttrium aluminum garnet, yttrium gallium garnet, artificial rutile and so on. Synthetic diamonds were first developed by Japan in 1955, but they were not mass-produced. Synthetic diamonds are rare in the market because they are more expensive than natural diamonds. Diamonds can be distinguished from similar gems by their unique hardness, density, dispersion and refractive index. For example, diamond-like cubic zirconia is colorless, with strong dispersibility (0.060), strong luster and high density of 5.8 g/cm3, which has obvious sense of gravity. Yttrium aluminum garnet has a soft dispersity, so it is difficult to distinguish it from diamonds with naked eyes.
cause
Modern science, technology and means provide new ideas and methods for exploring the formation of diamonds. 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. Carbon element crystallizes into graphite (black) at high temperature and high pressure, while it crystallizes into precious diamond (white) at high temperature, extremely high pressure and reducing environment (usually anoxic environment). 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 the depth of 150-200km) and 1 100- 1500 degrees Celsius. Although diamonds can be formed in various periods/stages of the earth's history in theory, most of the mines currently mined were mainly formed in two periods: 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 deep in the earth are brought to the surface or shallow part of the earth by volcanic activities, and this magma is mostly produced in the form of rock tubes, so it is commonly known as "tube ore" (primary ore). Kimberlite or K-Mg lamprophyre containing diamonds is exposed on the surface and weathered and broken by the external forces of the earth such as wind, rain and rain. Under the scouring of water, the broken protoliths and drill bits are taken to the riverbed and even the coastal zone to multiply, forming alluvial sand deposits (or secondary deposits).
Mingzuan
The world's largest 10 diamond.
1. "Cullinan". 190565438+1October 2 1 was discovered in Primir mine, South Africa. Pure and transparent, light blue tone, weighing 3 106 carats. Later, it was processed into 9 big diamonds and 96 small diamonds. One of the largest one is called "African Star I", which is water-drop shaped and embedded in the scepter of the king of England. The second largest is called "Africa Star II", which is square with 64 faces and weighs 3 17 carats. It is embedded in the crown of the British Empire.
2. braganca. Discovered in 1725, it is the largest diamond found in Brazil. Almost colorless, only slightly yellow, weighing 1680 carats. Then he disappeared. Some people suspect that this diamond may be later identified by more authoritative organizations and found to be topaz instead of diamond.
3. A big unnamed diamond. 19 19 A gem diamond weighing 1500 carats was found in Primir mine, and its color was similar to that of Cullinan. So some people think that it and Cullinan broke off from the same big crystal, so this diamond has no special name.
4. Orik. 1893, discovered in Jaggers Fontaine diamond mine in Orange Free State, South Africa. Smooth and transparent, blue and white, excellent luster, is a high-quality diamond. The largest one weighs 69.68 carats and is called "extremely noble".
5. Star of Sierra Leone. Sierra Leone's diamonds are famous for their good quality, large volume and octahedral crystal shape. The Star of Sierra Leone was discovered in the diamond mine of Youngma in February of 1972, weighing 968.9 carats and colorless.
6. Coleman DeDios. It is the largest diamond discovered in Brazil after Blagangza's discovery, weighing 922.5 carats, with excellent blue and white color.
7.Kohinur is the oldest known diamond in the world. According to legend, it was discovered in Golda, a famous ancient diamond mining area in India, as early as13rd century. The original stone weighs about 800 carats and is called "Kushinur". Later, it was processed into an oval shape, weighing 108.83 carats, colorless (slightly gray) and renamed as "Mountain of Light".
8. The Great Mughal is also one of the world-famous ancient diamonds. Found in Kola mining area, India, about 1630 to 1650. The original stone weighs 787.5 carats and has been processed into a rose shape, but its whereabouts are unknown.
9.Weyie River, 1945 Large diamonds found in the Voie Valley placer in Sierra Leone. The original stone weighs 770 carats, is almost colorless and of good quality. After that, it was cut into 30 cut diamonds. The largest one, 3 1.35 carats, was named "Victory Diamond".
10. Hsi Chin, 1986, discovered in Primir mine. The original stone weighs 755.50 carats and is dark golden brown. Later, a large diamond of 545.67 carats was ground. This is the largest cut diamond at present. This diamond is now embedded in the scepter of the King of Thailand.
Other diamonds
The history of human exploitation and utilization of diamonds has been thousands of years, but from ancient times to now, gem-grade diamonds larger than 20 carats are quite rare. Diamonds larger than 100 carat are regarded as national treasures. It is said that there are more than 1900 extra-large diamonds larger than 1000 carats found in the world at present, of which 21000 are larger than 500 carats, and only 2 are larger than1000 carats. Up to now, the largest diamond in the world was found in Premier, Zaire, South Africa on127 October, 1905+65438. This diamond is named Cullinan and weighs 3 106 carats. It is 100 mm long, 65 mm wide and 50 mm thick. Gem experts estimate Cullinan's value as high as $7.5 billion. 1907, the local government of transvaal province presented this giant diamond to King Edward VII of England. The king of England handed over the project of processing this giant diamond to the famous Dutch company Ascher, which once processed "noble" diamonds. After the company took over the project, it studied this giant diamond for several months. On February 1908 and 10, the giant diamond was cut into several large pieces and processed into 9 large diamonds and 98 small diamonds, leaving a rough stone (weighing 9.5 carats) unprocessed. The total amount of finished diamonds processed is 1063.65 carats, and the largest diamond processed is named "Cullinan No.1", also known as Africa Star, weighing 530.02 carats, which is a pear-shaped faceted diamond. "Cullinan II" is a chamfered rectangular drill, weighing 3 17.4 carats. Cullinan III is a pear-shaped diamond weighing 95 carats, Cullinan IV is a square diamond weighing 64 carats, a heart-shaped diamond weighing 19 carats, two horse-eye diamonds weighing l10.5 carats and 8.8 carats respectively, and the last two diamonds are rectangular diamonds (weighing 6.8 carats) and rugby diamonds (football diamonds).
/kloc-At the beginning of the 7th century, a rough diamond weighing 309 carats was found in the diamond placer in Golconda, India, and was later named Orlov Diamond. At that time, a famous diamond processing expert planned to process it into the shape of "Indian Rose" according to Shah Han Zhe's will, but failed to do it completely, and the weight was reduced a lot (only 189.62 carats). According to legend, this wonderful, rare and flawless diamond was later made into the eyes of an idol in the Seringa temple in India. After Delhi was captured by the Persian king Nader Gil in 1739, this diamond was decorated on Nader Gil's throne and named "Gil onur". Then the diamond was stolen and fell into the hands of an Armenian. 1767, he deposited the diamonds in a bank in Amsterdam. 1772, he sold diamonds to Ivan, a jeweler, and Ivan bought them for 400,000 rubles to Count orlov in 1773. In the same year, orlov presented this diamond to Catherine II as a gift for her naming day. Later, it was welded into a carved silver base and inlaid on the top of the Russian scepter. Orlov diamonds are perfect and very rare. Slightly blue-green, there are several tiny yellowish inclusions in the crystal. This diamond is 22 mm thick, 3 1-32 mm wide and 35 mm long. At present, this diamond is treasured in the Diamond Foundation of the former Soviet Union, and another famous diamond "Shah" was presented to the czar's government by Persian Prince Mirza on 1829, aiming at repairing the relations between the two countries deteriorated by the murder of the Russian embassy in Persia. The Shah diamond weighs 88.7 carats. It is light yellow and flawless, except for some small cracks in the deep crystal. The three polished surfaces are engraved with Persian characters, meaning "Burhan-nizam-Shah II, 1000 (A.D. 159 1 year)". This diamond fell into their hands after India was occupied by the Great Mughal Dynasty 2. The second inscription means "Han Zhe Shah, son of Han Zhe Gil Shah, 105 1 year (A.D. 164 1 year)". The third paragraph means "ruler Kadzar-Faget-Ali-Shah Sultan, 1242. (King of Persia, 1842). This diamond was occupied by the Shah of Nadjir in about 1739 when the great Mughal dynasty was occupied. No one knows where this diamond was collected. It is inferred that it may find Kangda placer in Hugele. Being able to carve an inscription on the incredibly hard "Shah" diamond shows that the skills of Persian artists at that time were unimaginable. The Archon of the Great Mughal Empire mentioned in the inscription, Shah Han Zhe, was in office from 1627 to 1666, and was captured by Jeb and spent the rest of his life in prison. Shah Hezhe rarely worships great gems. He has a special studio and even goes there to sort out and ponder gems. His son Jeb not only usurped the throne, but also seized his father's treasure. 1665, a famous traveler made a fascinating description of the throne of the Great Mughal Dynasty, which was decorated with a lot of precious stones. A diamond weighing 80-90 carats hangs on the canopy of the throne at the side of the audience, surrounded by many emeralds and rubies. This may be "Shah", hanging between the big Mughal and the worshippers as a treasure of protection. There is also a very beautiful diamond, named "Sangxi" diamond, which weighs 55 carats. It is said that this diamond was embedded in the helmet of the warrior Carl and was lost in a battle.
1589, "Sansi" appeared in the treasure house of Portuguese king Anton. Later, it was sold to France's Scud Sanxi for 65,438+10,000 old francs. "Sangxi" diamond has a long history as a family heirloom. Later, it was presented to King Genglihe II of France and included in the list of treasures in France. On 1792, this diamond was looted. 1830, "Sangxi" was bought by Demidoff, the descendant of a Ukrainian factory owner, and the transaction price was 500,000 francs. The French government fought a lawsuit on this matter, and five years later the diamond was awarded to Demidoff. There is also a touching story about the 4 10 carat "regent" diamond. It is said that it was picked up by an Indian slave in the well-known Golconda mine in 170 1 year. He wanted to use this diamond to change his life and be free, so he took advantage of people's inattention to raise a T-pick and hit it on his thigh, bleeding profusely. The Indians endured great pain, hiding diamonds in the depths of the wound and wrapping the wound with leaves as bandages. He found an English sailor and prepared to exchange his freedom. After seeing this huge diamond, the sailor hoped that he couldn't get it right away, so he was prepared to pay everything for it. Sailors and slaves soon settled down, and the sailors hid the Indians in jute and in the cabin without telling the captain. When the ships sailed into the high seas, the sailors gave the slaves food at night, killed them with daggers, and threw the victims into the sea while they were eating. After the ship landed in Madras, the sailors sold the diamonds to Sir Peter, the British governor of the city, for 20,000 pounds. When the sailor got the money, he quickly squandered it and finally hanged himself. 17 17 Peter sold the diamonds to the French regent Oranski for 3.4 million gold francs. The duke ordered the diamond to be processed, and the diamond "Regent" was born. The birth of this diamond is hard. It took two years to polish and polish. The processed weight is 140.5 carats. When Ludovici XIV was crowned in 65,438+0722, diamonds were embedded in his crown. In the early days of the French Revolution, just like the king. Later, a German jeweler sold it to Napoleon. /kloc-In the 1990s of 0/8, it was used as collateral by Napoleon to launch an expedition. 1940 When Hitler captured Paris, diamonds were hidden in the partition of the marble fireplace in Shambo. This diamond is currently on display in the Louvre. The particle size of diamond is 30 X 29 X 19mm. The cutting of diamond is dazzling and exquisite, and its luster has different repercussions from "fire". 1762, Ye, a talented court jeweler, won praise for the gorgeous and exquisite jewelry made by the king at the coronation ceremony of Catherine II. He created a new world with brilliant diamonds. The crown is always inlaid with 4936 diamonds, weighing 2858 carats. The whole crown weighs1907g, and the "spinel" diamond decorating the crown weighs 398.72 carats.
The oldest diamond in the world-Margot diamond
Mago diamond, weighing 787.50 carats, is the earliest giant rough stone found in history, which was discovered in Gorkon on 1304. This area is also the place where diamond deposits were first discovered in the world. Up to now, its weight ranks fourth in the original diamond. The crystal shape of the original stone is incomplete, but it is colorless and transparent, which is extremely precious because of its bright fire color. After many twists and turns, the original stone was stolen many times and finally fell into the hands of Queen Victoria. After careful design, it was cut into several diamonds. Two of the most famous ones are Kon-i-noor, weighing 108.93 carats, oval, embedded in the crown of the Queen Mother; The other one, named orlov, weighs 189.60 carats and is shaped like a rose. Now it is kept in the Kremlin, and orlov's diamonds rank ninth in the weight of finished diamonds.