In people's jewelry luxury goods, diamonds refer to polished diamonds, which are also a symbol of love and loyalty. People are curious about how diamonds form. Let me explain to you in detail how diamonds are formed. Reasons for the formation of diamonds Structural characteristics of diamonds: Diamonds are composed of carbon, which is a crystal of carbon with a hardness of 10. It is the hardest natural mineral in nature, with a density of 3.53 (0.01) g/cubic centimeter, a refractive index of 2.417, and a dispersion of 0.044. It is the product of diamond cutting and grinding. In diamond About one-fifth of the minerals can reach gem quality and are called gem-grade diamonds. They are also called "rough diamonds" or "rough diamonds" abroad. After the rough is cut and polished into a cutting shape, it is called a loose diamond, and abroad it is called a finished diamond or polished diamond. The English name Diamond comes from the Greek word amount, which means "hard, inviolable, invincible". Both diamond and graphite are composed of carbon. Diamond and graphite are formed under different temperature and pressure conditions, and they can transform into each other under changes in temperature and pressure conditions. Diamond is a cubic crystal with a hardness of 10, and graphite is a hexagonal crystal with a hardness of 1. They have different crystal structures and are two homogeneous polymorphs of crystalline carbon. Only under certain pressure and temperature can carbon crystallize into diamond. Formation of diamonds: The earliest natural diamonds were formed inside the earth at a temperature of 900-1600°C and a pressure of (4.5-6)×109Pa, which is equivalent to a depth of 130-200km underground. In theory, diamonds can form at any time as long as the conditions are met. Most of the diamonds currently mined were formed between 3.3 billion years ago and 1.2-1.7 billion years ago. The carbon that forms diamonds comes from molten magma in the Earth's mantle, or from movement in the Earth's crust. Ribbons of carbon in the Earth's crust collect deep within the Earth and crystallize into diamonds under the right conditions. There is also an external way to produce diamonds. When a meteorite hits a continent, the high temperature and pressure generated instantly may also produce diamonds. However, diamonds produced in this way are often small, of poor quality, generally have no economic value, and cannot be used as diamonds for jewelry processing. Discovery of Diamonds: Diamonds were first discovered in India. With people's desire for diamonds, diamond exploration and mining are becoming more and more popular. Diamond deposits are divided into primary ores and secondary ores. Primary ores are produced by the earth's geological movements. Earthquakes and volcanic activity bring diamond-rich minerals to areas at or near the surface, most of which are diamond-rich kimberlites and lamprophyres, as well as fills near craters and roots in rock walls and bedrock sediment. Under the influence of nature, secondary ores are transported and deposited from primary ores. Most of them have been washed away by weathering and rainwater, and remain on hillsides, rivers and coasts to form mineral deposits, mostly placer deposits. The formation and discovery process of diamonds is roughly like this, unlike precious metals such as gold. Since the 21st century, diamond prices have maintained a steady growth trend and have gradually become the first choice for investors. The simple identification method of diamonds requires the assistance of a 10-20x magnifying glass and a few simple observations. Observe the girdle of the diamond. It is best to use this method if you want to sand your waist. Because diamonds are harder than any imitation, there will be no fine lines like imitations. The girdle of the diamond is grainy. Diamonds are harder than imitations, and the facets of imitations are often blunter than diamonds, but the facets of diamonds must be sharp. Because diamonds are harder than imitations, the faceted edges of imitations often wear away. If the diamond has a natural surface, there is a chance to find the diamond's unique "triangular growth line" on the natural surface. If a diamond is broken, its appearance is usually stepped, while imitations are curved or shell-like. Hardness Check Diamonds are the hardest known natural substances and nothing can mark them. If it could, it wouldn't be a diamond. Heat conduction experiments breathe while debating diamonds and other similar projects. In the case of diamonds, water mist condensed on its surface should evaporate faster than water mist on other items. This is because diamond has a high thermal conductivity. Observation method Reflected light Use a magnifying glass to observe that the girdle of the diamond is very finely frosted, and the reflected light sparkles. This property of diamonds is unique. Look at the growth points. Observe under a magnifying glass. There are often grooves and triangular growth points on the crystal surface of real diamonds. There are three types of fakes: ① Ordinary glass plus alumina. Due to the increased refractive index and dispersion, it is easy to accidentally enter, but the hardness is relatively high. Low. ②Imitated from chemically synthesized sapphire and colorless spinel, the hardness is similar, but the refractive index is low and there is birefringence, and ghost images can be seen under a magnifying glass. Pencil Identification The chemical composition of pencils is carbon, just like diamonds, but with different physical structures. Therefore, many people use a pencil to detect the authenticity of diamonds. This is a more practical and effective method. When appraising, they first wet the diamond with water and then lightly mark it with a pencil. On the crystal surface of a real diamond, there will be no traces where the pencil scratches. However, if it is not a diamond but a material such as glass or crystal, traces will be left on the surface. It is usually marked with a pencil to identify the authenticity of the diamond. This one has high hardness and good refraction, but it will reflect more colored light when rotated, which is obviously different from the original product that only reflects weak yellow and blue light when rotated. Diamond Cutting Process A rough diamond looks inconspicuous, but it must be carefully cut, polished, and processed before it can become the shining diamond we are accustomed to. Therefore, the turning of diamonds directly affects the value of diamonds, which will be introduced in detail below.

Of course, the ideal cutting effect is to maintain the maximum weight of the diamond, minimize imperfections, and fully display the beauty of the diamond to make it sparkle. The general cutting process includes the following steps: 1. Marking: This is the first step in diamond cutting. First, inspect the rough diamond and mark the surface of the diamond. The people doing this work are experienced and proficient in processing technology. The ultimate goal is to produce the largest, cleanest, and most perfect diamonds to maximize their value. The scribe must pay attention to two things: maintain maximum weight and minimize inclusions. The scribe uses a magnifying glass to study the structure of the rough diamond. In the case of large diamonds, this work may take several months, while in the case of ordinary rough diamonds, it may take several minutes. However, no matter how small the rough diamond is, each diamond must undergo detailed inspection before a correct judgment can be made. The scribe marked the rough diamond with India ink, indicating the line along which the rough diamond was to be divided. Typically, the lines are drawn as closely as possible along the direction of the diamond's natural grain. The split cutter places the drawn diamond blank on the holder, then uses another diamond to cut a dent along the dividing line, then puts a square knife on the dent and taps it with appropriate force. . The diamond will split into two or more pieces along the grain direction. Sawing Most diamonds are not suitable for splitting and require a saw for cutting. Since only diamonds can cut diamonds, the saw blades are phosphor bronze discs with edges coated with diamond powder and lubricant. The diamond is fixed on the fixture, and the saw disc rotates at high speed to cut the diamond. The introduction of modern laser technology into diamond cutting greatly improves the processing efficiency of diamond blanks. The diamonds that have been sawn or split into the desired shape are sent to the rounding department for rounding and shaping, that is, according to the design requirements, the diamonds are made into common cut flowers such as round, heart-shaped, oval, pointed, emerald, etc. shape, or other special shapes. Since diamond is by far the hardest natural substance recognized by humans, only diamonds can polish diamonds, and the hardness of diamonds varies slightly in all directions. Therefore, when polishing, you must rely on experience to grasp the basic shapes of diamonds: trihedron, octahedron, dodecahedron and crystal characteristics. The general method is to rotate the drill blank on a lathe at high speed, and then use the diamond on the other arm to round the rotating drill blank. Polished on a cast iron disc coated with diamond powder and lubricating oil, all facets (facets) are turned, making the diamond sparkle. The polishing process is usually to first make 8 large surfaces on the bottom layer, and then make 16 small surfaces. There is a culet with 25 facets. From these facets extend the triangular facet, the kite facet, the girdle facet, and a total of 33 facets. Such a round diamond has 58 facets, and if there are no culet facets, it has 57 facets. Not every rough diamond needs to go through all the above processes, depending on the characteristics of the rough diamond and the goals to be achieved. For example, the "flat" rough diamond mentioned above may not need to be cut, or an emerald diamond may not need to be rounded. However, for any rough diamond, there are two essential processes, namely "scribing", "chipping" and polishing. A finely crafted diamond produces petals whose surface positions and angles are precisely calculated, allowing the diamond to shine at its most brilliant. With the advancement of science and technology, the introduction of laser technology and computer technology can make the design and cutting of diamond blanks more precise. The chemical composition of diamonds is carbon. Carbon is the only single element in gemstones and belongs to the equiaxed crystal system. It often contains 0.05%-0.2% impurity elements, the most important of which are N and B. Their presence is related to the type and properties of the diamond. Most crystals are octahedrons, rhombohedral dodecahedrons, tetrahedrons, and their aggregates. Pure diamonds are colorless and transparent, showing different colors due to the mixture of trace elements. Intense diamond luster. The refractive index is 2.417 and the dispersion is moderate, 0.044. Isotropic objects. Thermal conductivity is 0.35 cal/cm/sec/degree. Tested with a thermal conductivity meter, the response is the most sensitive. With a hardness of 10, it is the hardest mineral currently known. Its absolute hardness is 1,000 times that of corundum and 150 times that of corundum. It is afraid of a heavy blow, which will cause it to be broken into pieces. One set completely cracked. Density is 3.52 g/cm3. Diamonds are luminous, emitting a faint cyan phosphorescence at night when exposed to sunlight. X-ray irradiation emits sky-blue fluorescence. The chemical properties of diamond are very stable. It is not easily soluble in acids and alkali at room temperature, and acids and alkali will not affect it. The difference between diamonds and similar gemstones and man-made diamonds. Common substitutes or fakes in the gem market include colorless gemstones, colorless spinel, cubic zirconia, strontium titanate, yttrium aluminum garnet, yttrium gallium garnet, artificial rutile, etc. Artificial diamonds were first successfully developed by Japan in 1955, but they were not mass-produced. Because synthetic diamonds are more expensive than natural diamonds, synthetic diamonds are rarely found on the market. Diamonds can be distinguished from similar gemstones by their unique hardness, density, dispersion, and refractive index. For example, diamond-like cubic zirconia is colorless, has strong dispersion (0.060), strong gloss, high density of 5.8g/cm3, and a heavy hand feel. Yttrium garnet has a soft dispersion and is difficult to distinguish from diamond by the naked eye.

To see how diamonds are formed, take a look at: 1. How are gold mines formed? 2. How is moonstone formed? 3. How is lightning formed? 4. How are lagoons formed? 5. How are the pearls of the shell formed?