157-643: The De Beers Group is a South African–British corporation that specializes in the diamond industry, including mining, exploration, retail, inscription, grading, trading and industrial diamond manufacturing. The company is active in open-pit, underground, large-scale alluvial and coastal mining. It operates in 35 countries with mining taking place in Botswana , Namibia , South Africa, and Canada. It also has an artisanal mining business, Gemfair , which operates in Sierra Leone . From its inception in 1888 until
314-485: A micron deep. This inscription helps distinguish Forevermark diamonds from other natural diamonds though, similarly to when distinguishing natural diamonds from synthetic diamonds , it requires specialist detection equipment to view. The inscription also helps maintain scarcity: the Forevermark website boasts that only a tiny percentage of diamonds qualify for the Forevermark brand. De Beers Diamond Jewellers (DBDJ)
471-745: A subduction zone . Siege of Kimberley 1900 1901 1902 The siege of Kimberley took place during the Second Boer War at Kimberley , Cape Colony (present-day South Africa), when Boer forces from the Orange Free State and the Transvaal besieged the diamond mining town. The Boers moved quickly to try to capture the area when war broke out between the British and the two Boer republics in October 1899. The town
628-491: A Christie's auction. In May 2009, a 7.03-carat (1.406 g) blue diamond fetched the highest price per carat ever paid for a diamond when it was sold at auction for 10.5 million Swiss francs (6.97 million euros, or US$ 9.5 million at the time). That record was, however, beaten the same year: a 5-carat (1.0 g) vivid pink diamond was sold for US$ 10.8 million in Hong Kong on December 1, 2009. Clarity
785-405: A German immigrant to Britain and later South Africa who had earlier founded mining company Anglo American with American financier J. P. Morgan , was elected to the board of De Beers. He built and consolidated the company's global monopoly over the diamond industry until his death in 1957. During this time, he was involved in several controversies, including price fixing and trust behaviour, and
942-654: A charge to our children in sign of the price we paid, The price that we paid for freedom that comes unsoiled to your hand; Read, revere and uncover, here are the victors laid, They who died for their City, being sons of the land”. Long Cecil , the gun manufactured in the De Beers workshops during the siege, is mounted on the stylobate (facing the Free State ), surrounded by shells from the Boer Long Tom . The Sanatorium Hotel, in which Cecil Rhodes stayed during
1099-453: A cigarette lighter, but house fires and blow torches are hot enough. Jewelers must be careful when molding the metal in a diamond ring. Diamond powder of an appropriate grain size (around 50 microns) burns with a shower of sparks after ignition from a flame. Consequently, pyrotechnic compositions based on synthetic diamond powder can be prepared. The resulting sparks are of the usual red-orange color, comparable to charcoal, but show
1256-727: A continuum with carbonatites , but the latter have too much oxygen for carbon to exist in a pure form. Instead, it is locked up in the mineral calcite ( Ca C O 3 ). All three of the diamond-bearing rocks (kimberlite, lamproite and lamprophyre) lack certain minerals ( melilite and kalsilite ) that are incompatible with diamond formation. In kimberlite , olivine is large and conspicuous, while lamproite has Ti- phlogopite and lamprophyre has biotite and amphibole . They are all derived from magma types that erupt rapidly from small amounts of melt, are rich in volatiles and magnesium oxide , and are less oxidizing than more common mantle melts such as basalt . These characteristics allow
1413-647: A cost of $ 157 million and named after Sam Nujoma, Namibia's founding president. This vessel, the world's most advanced diamond exploration and sampling vessel, began full operations in June 2017. De Beers Consolidated Mines is responsible for the De Beers mining in South Africa . It is 74% owned by De Beers and 26% by a board-based black economic empowerment partner, Ponahalo Investments. There are two mines – Venetia and Voorspoed. In 2008, De Beers began production at
1570-452: A diamond to fluoresce. Diamonds can fluoresce in a variety of colors including blue (most common), orange, yellow, white, green and very rarely red and purple. Although the causes are not well understood, variations in the atomic structure, such as the number of nitrogen atoms present are thought to contribute to the phenomenon. Diamonds can be identified by their high thermal conductivity (900– 2320 W·m ·K ). Their high refractive index
1727-480: A gemstone. Because it can only be scratched by other diamonds, it maintains its polish extremely well. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in engagement or wedding rings , which are often worn every day. The hardest natural diamonds mostly originate from the Copeton and Bingara fields located in
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#17327823411871884-593: A gun named Long Cecil in the company workshops. In 1898, diamonds were discovered on farms near Pretoria , Transvaal. One led to the discovery of the Premier Mine . The Premier Mine was registered in 1902 and the Cullinan Diamond , the largest rough diamond ever discovered, was found there in 1905. (The Premier Mine was renamed the Cullinan Mine in 2003.) However, its owner refused to join
2041-466: A lab-grown diamond brand to sell jewellery directly to consumers. International Institute of Diamond Valuation Diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic . Diamond as a form of carbon is a tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known as graphite
2198-475: A metallic fluid. The extreme conditions required for this to occur are present in the ice giants Neptune and Uranus . Both planets are made up of approximately 10 percent carbon and could hypothetically contain oceans of liquid carbon. Since large quantities of metallic fluid can affect the magnetic field, this could serve as an explanation as to why the geographic and magnetic poles of the two planets are unaligned. The most common crystal structure of diamond
2355-403: A pale blue flame, and continues to burn after the source of heat is removed. By contrast, in air the combustion will cease as soon as the heat is removed because the oxygen is diluted with nitrogen. A clear, flawless, transparent diamond is completely converted to carbon dioxide; any impurities will be left as ash. Heat generated from cutting a diamond will not ignite the diamond, and neither will
2512-554: A relatively high optical dispersion . Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle , although a few have come from as deep as 800 kilometres (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (hundreds to tens of million years ago), they were carried to
2669-413: A sterilized dictator acting in an atmosphere too tenuous to support his vitality but sufficient to preserve it from extinction. He was subject to the authority of the military commandant, a galling position for a distinguished statesman who had not a high opinion of the professional capacity of the British officer. In practice, unlike Baden Powell at Mafeking , Kekewich did not have free rein to conduct
2826-463: A transition between graphite and diamond are well established theoretically and experimentally. The equilibrium pressure varies linearly with temperature, between 1.7 GPa at 0 K and 12 GPa at 5000 K (the diamond/graphite/liquid triple point ). However, the phases have a wide region about this line where they can coexist. At standard temperature and pressure , 20 °C (293 K) and 1 standard atmosphere (0.10 MPa),
2983-467: A very linear trajectory which is explained by their high density. Diamond also reacts with fluorine gas above about 700 °C (1,292 °F). Diamond has a wide band gap of 5.5 eV corresponding to the deep ultraviolet wavelength of 225 nanometers. This means that pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities. The diamond crystal lattice
3140-425: A volcanic rock. There are many theories for its origin, including formation in a star, but no consensus. Diamond is the hardest material on the qualitative Mohs scale . To conduct the quantitative Vickers hardness test , samples of materials are struck with a pyramid of standardized dimensions using a known force – a diamond crystal is used for the pyramid to permit a wide range of materials to be tested. From
3297-408: A watch tower, shells, and a gun, known as Long Cecil , for the defenders in order to supplement their inadequate weapons. Long Cecil was rifled with a bore of 100 millimetres (3.9 in) capable of propelling a 13-kilogram (29 lb) shell 6,000 metres (6,600 yd). The gun was completed on 21 January 1900, and successfully test fired against a previously untouchable Boer position north of
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#17327823411873454-449: Is 0.01% for nickel and even less for cobalt. Virtually any element can be introduced to diamond by ion implantation. Nitrogen is by far the most common impurity found in gem diamonds and is responsible for the yellow and brown color in diamonds. Boron is responsible for the blue color. Color in diamond has two additional sources: irradiation (usually by alpha particles), that causes the color in green diamonds, and plastic deformation of
3611-415: Is a solid form of pure carbon with its atoms arranged in a crystal. Solid carbon comes in different forms known as allotropes depending on the type of chemical bond. The two most common allotropes of pure carbon are diamond and graphite . In graphite, the bonds are sp orbital hybrids and the atoms form in planes, with each bound to three nearest neighbors, 120 degrees apart. In diamond, they are sp and
3768-420: Is aided by isotopic dating and modeling of the geological history. Then surveyors must go to the area and collect samples, looking for kimberlite fragments or indicator minerals . The latter have compositions that reflect the conditions where diamonds form, such as extreme melt depletion or high pressures in eclogites . However, indicator minerals can be misleading; a better approach is geothermobarometry , where
3925-728: Is also indicative, but other materials have similar refractivity. Diamonds are extremely rare, with concentrations of at most parts per billion in source rock. Before the 20th century, most diamonds were found in alluvial deposits . Loose diamonds are also found along existing and ancient shorelines , where they tend to accumulate because of their size and density. Rarely, they have been found in glacial till (notably in Wisconsin and Indiana ), but these deposits are not of commercial quality. These types of deposit were derived from localized igneous intrusions through weathering and transport by wind or water . Most diamonds come from
4082-405: Is another mechanical property toughness , which is a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 50–65 MPa ·m . This value is good compared to other ceramic materials, but poor compared to most engineering materials such as engineering alloys, which typically exhibit toughness over 80 MPa·m . As with any material,
4239-414: Is called diamond cubic . It is formed of unit cells (see the figure) stacked together. Although there are 18 atoms in the figure, each corner atom is shared by eight unit cells and each atom in the center of a face is shared by two, so there are a total of eight atoms per unit cell. The length of each side of the unit cell is denoted by a and is 3.567 angstroms . The nearest neighbor distance in
4396-402: Is exceptionally strong, and only atoms of nitrogen , boron , and hydrogen can be introduced into diamond during the growth at significant concentrations (up to atomic percents). Transition metals nickel and cobalt , which are commonly used for growth of synthetic diamond by high-pressure high-temperature techniques, have been detected in diamond as individual atoms; the maximum concentration
4553-419: Is formed of layers stacked in a repeating ABCABC ... pattern. Diamonds can also form an ABAB ... structure, which is known as hexagonal diamond or lonsdaleite , but this is far less common and is formed under different conditions from cubic carbon. Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles . As diamond's crystal structure has a cubic arrangement of
4710-412: Is higher for flawless, pure crystals oriented to the <111> direction (along the longest diagonal of the cubic diamond lattice). Therefore, whereas it might be possible to scratch some diamonds with other materials, such as boron nitride , the hardest diamonds can only be scratched by other diamonds and nanocrystalline diamond aggregates . The hardness of diamond contributes to its suitability as
4867-404: Is hybrid rock with a chaotic mixture of small minerals and rock fragments ( clasts ) up to the size of watermelons. They are a mixture of xenocrysts and xenoliths (minerals and rocks carried up from the lower crust and mantle), pieces of surface rock, altered minerals such as serpentine , and new minerals that crystallized during the eruption. The texture varies with depth. The composition forms
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5024-647: Is in the form of micro/nanoscale wires or needles (~100–300 nanometers in diameter, micrometers long), they can be elastically stretched by as much as 9–10 percent tensile strain without failure, with a maximum local tensile stress of about 89–98 GPa , very close to the theoretical limit for this material. Other specialized applications also exist or are being developed, including use as semiconductors : some blue diamonds are natural semiconductors, in contrast to most diamonds, which are excellent electrical insulators . The conductivity and blue color originate from boron impurity. Boron substitutes for carbon atoms in
5181-578: Is made up of a series of joint ventures and wholly owned operations. The joint ventures are: The wholly owned operations are in southern Africa and Canada. Also wholly owned are Forevermark , De Beers Jewellers, the International Institute of Diamond Valuation, De Beers Ventures, the International Institute of Diamond Grading & Research and Element Six (Umicore has a 40% stake in Element Six's abrasives division). Forevermark
5338-403: Is not to interfere in military matters.” The conflict at Kimberley started on 14 October 1899. Colonel Baden-Powell , anticipating the inevitable onset of hostilities, encouraged all the women and children to leave the town. Some civilians left in a special train, escorted as far as Vryburg by an armoured train . On the return journey, the armoured train was captured in the first action of
5495-477: Is one of the 4C's (color, clarity, cut and carat weight) that helps in identifying the quality of diamonds. The Gemological Institute of America (GIA) developed 11 clarity scales to decide the quality of a diamond for its sale value. The GIA clarity scale spans from Flawless (FL) to included (I) having internally flawless (IF), very, very slightly included (VVS), very slightly included (VS) and slightly included (SI) in between. Impurities in natural diamonds are due to
5652-797: Is partially oxidized. The oxidized surface can be reduced by heat treatment under hydrogen flow. That is to say, this heat treatment partially removes oxygen-containing functional groups. But diamonds (sp C) are unstable against high temperature (above about 400 °C (752 °F)) under atmospheric pressure. The structure gradually changes into sp C above this temperature. Thus, diamonds should be reduced below this temperature. At room temperature, diamonds do not react with any chemical reagents including strong acids and bases. In an atmosphere of pure oxygen, diamond has an ignition point that ranges from 690 °C (1,274 °F) to 840 °C (1,540 °F); smaller crystals tend to burn more easily. It increases in temperature from red to white heat and burns with
5809-769: Is possible to treat regular diamonds under a combination of high pressure and high temperature to produce diamonds that are harder than the diamonds used in hardness gauges. Diamonds cut glass, but this does not positively identify a diamond because other materials, such as quartz, also lie above glass on the Mohs scale and can also cut it. Diamonds can scratch other diamonds, but this can result in damage to one or both stones. Hardness tests are infrequently used in practical gemology because of their potentially destructive nature. The extreme hardness and high value of diamond means that gems are typically polished slowly, using painstaking traditional techniques and greater attention to detail than
5966-452: Is the chemically stable form of carbon at room temperature and pressure , but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in
6123-454: Is the case with most other gemstones; these tend to result in extremely flat, highly polished facets with exceptionally sharp facet edges. Diamonds also possess an extremely high refractive index and fairly high dispersion. Taken together, these factors affect the overall appearance of a polished diamond and most diamantaires still rely upon skilled use of a loupe (magnifying glass) to identify diamonds "by eye". Somewhat related to hardness
6280-739: The Earth's mantle , and most of this section discusses those diamonds. However, there are other sources. Some blocks of the crust, or terranes , have been buried deep enough as the crust thickened so they experienced ultra-high-pressure metamorphism . These have evenly distributed microdiamonds that show no sign of transport by magma. In addition, when meteorites strike the ground, the shock wave can produce high enough temperatures and pressures for microdiamonds and nanodiamonds to form. Impact-type microdiamonds can be used as an indicator of ancient impact craters. Popigai impact structure in Russia may have
6437-596: The Kimberley Star , which was instituted by Mayor H. A. Oliver. Since the medal was not an official one, it could not be worn with military uniforms. The official awards for the siege and relief of Kimberley were, respectively, the "Defence of Kimberley" and "Relief of Kimberley" clasps to the Queen's South Africa Medal . The British established a concentration camp at Kimberley to hold interned Boer women and children, as well as black refugees. A memorial outside
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6594-566: The New England area in New South Wales , Australia. These diamonds are generally small, perfect to semiperfect octahedra, and are used to polish other diamonds. Their hardness is associated with the crystal growth form, which is single-stage crystal growth. Most other diamonds show more evidence of multiple growth stages, which produce inclusions, flaws, and defect planes in the crystal lattice, all of which affect their hardness. It
6751-603: The Riet River . On 13 February, Roberts activated the second part of his plan, that involved French's cavalry separating from the slower main force and piercing forward quickly by swinging northwards, just east of Jacobsdal , to cross the Modder River at Klip Drift. As French's column neared the Modder River on 13 February, a force of about 1,000 Boers made contact with his right flank. French wheeled his right and centre brigades towards their enemy, thereby allowing
6908-1243: The Snap Lake mine in the Northwest Territories , Canada; this was the first De Beers mine outside Africa and was Canada's first completely underground diamond mine. However, production was suspended when the mine was put on care and maintenance in 2015. De Beers opened the Victor mine in Ontario , Canada, the same year, a day after Snap Lake. This was followed by the opening of the company's third mine in Canada, Gahcho Kue , in September 2016. Trading of rough diamonds takes place through two channels – De Beers Global Sightholder Sales (GSS) and De Beers Auction Sales. GSS sells about 90% of De Beers's rough diamonds, by value, and features wholly owned and joint venture operations in South Africa (De Beers Sightholder Sales South Africa), Botswana (DTCB), and Namibia (NDTC). They sort, value and sell 33% (2013) of
7065-559: The Wawa belt of the Superior province in Canada and microdiamonds in the island arc of Japan are found in a type of rock called lamprophyre . Kimberlites can be found in narrow (1 to 4 meters) dikes and sills, and in pipes with diameters that range from about 75 m to 1.5 km. Fresh rock is dark bluish green to greenish gray, but after exposure rapidly turns brown and crumbles. It
7222-519: The breakdown of Anglo-Boer relations leading up to the war, would antagonise the Boers. Consequently, the mayor of Kimberley, as well as various associates of Rhodes, tried to discourage him. However, Rhodes ignored the advice and moved into the town just prior to the onset of the siege, very narrowly evading capture when the Boer ultimatum expired at 5 pm on 11 October while he was still en route . It
7379-436: The lithosphere . Such depths occur below cratons in mantle keels , the thickest part of the lithosphere. These regions have high enough pressure and temperature to allow diamonds to form and they are not convecting, so diamonds can be stored for billions of years until a kimberlite eruption samples them. Host rocks in a mantle keel include harzburgite and lherzolite , two type of peridotite . The most dominant rock type in
7536-536: The normal color range , and applies a grading scale from "D" (colorless) to "Z" (light yellow). Yellow diamonds of high color saturation or a different color, such as pink or blue, are called fancy colored diamonds and fall under a different grading scale. In 2008, the Wittelsbach Diamond , a 35.56-carat (7.112 g) blue diamond once belonging to the King of Spain, fetched over US$ 24 million at
7693-402: The upper mantle , peridotite is an igneous rock consisting mostly of the minerals olivine and pyroxene ; it is low in silica and high in magnesium . However, diamonds in peridotite rarely survive the trip to the surface. Another common source that does keep diamonds intact is eclogite , a metamorphic rock that typically forms from basalt as an oceanic plate plunges into the mantle at
7850-436: The 'Palladio' suite. A 2010 commercial for Verizon Wireless parodied the De Beers spots. In May 2018, De Beers introduced a new brand of jewellery called "Lightbox" made with synthetic diamonds . The synthetic stones start at $ 200 for a quarter carat to $ 800 for a full carat diamond. The new lab-grown diamonds retail for about one-tenth the cost of naturally occurring diamonds. The new brand began selling in September 2018 and
8007-461: The Boer redoubt at Carter's Ridge, west of the town. Kekewich's men held the belief that the action would assist Methuen's relief column at Magersfontein by keeping more Boers occupied at Kimberley. A detachment of 40 members of Cape Police and Light Horse under the command of Major Scott-Turner of the Black Watch set out at midnight and completely surprised their enemy in the early hours of
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#17327823411878164-423: The Boer capitals were assaulted. The first attempt at relief of Kimberley under Lord Methuen was stopped at the battles of Modder River and Magersfontein . The 124-day siege was finally relieved on 15 February 1900 by a cavalry division under Lieutenant-General John French , part of a larger force under Lord Roberts . The battle against the Boer general Piet Cronjé continued at Paardeberg immediately after
8321-424: The British push northwards. French's men set out from Klip Drift at 9:30 am on 15 February on the last stage of their journey to Kimberley, and were soon engaged by the Boer force sent to block them. Rifle fire came from the river in the east while artillery shells rained from the hills in the north west; the route to Kimberley lay straight ahead through the crossfire, so French ordered a bold cavalry charge down
8478-563: The Cape Police (recalled from various outposts along the railway line), 2,000 irregular troops , the Kimberley Light Horse, and a battery of obsolete seven-pounder guns. Eight Maxim machine guns were mounted on redoubts built atop tailing heaps around the town. Cecil John Rhodes, the founder of De Beers, was contemplating moving into the town. The citizens feared that his presence there, given his prominent role in
8635-489: The De Beers Company released a statement of a values change, promising the world that it is committed to not using slave labor within the company. De Beers successfully advertised diamonds to manipulate consumer demand. One of the most effective marketing strategies has been the marketing of diamonds as a symbol of love and commitment. Copywriter Frances Gerety (1916–1999) working for N. W. Ayer & Son coined
8792-553: The De Beers cartel. Instead, the mine started selling to a pair of independent dealers named Bernard and Ernest Oppenheimer , thereby weakening the De Beers stronghold. Francis Oats , who became Chairman of De Beers in 1908, was dismissive of the threats from the Premier Mine and the finds in German South West Africa . However, production soon equalled all of the De Beers mines combined. Ernest Oppenheimer
8949-454: The De Beers channel, as well as increasingly negative publicity surrounding blood diamonds , which forced De Beers to protect its image by limiting sales to its own mined products. The combination of a more fragmented and thus more competitive diamond market, increased transparency, and greater liquidity , caused De Beers's market share of rough diamonds to fall from as high as 90% in the 1980s to 29.5% in 2019. Seeing these developing trends,
9106-424: The Earth. Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen ). Small numbers of defects or impurities (about one per million of lattice atoms) can color a diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a very high refractive index and
9263-659: The Newton Dutch Reformed Church commemorates those that died in the camp. The Honoured Dead Memorial , a sandstone edifice commissioned by Cecil Rhodes and designed by Sir Herbert Baker , was erected to commemorate the defenders who fell during the siege. Twenty-seven soldiers are entombed in the memorial, which was made from stone quarried in the Matopo Hills in Rhodesia (today Zimbabwe). It bears an inscription by Rudyard Kipling : “This for
9420-648: The Oppenheimer family announced in November 2011 its intention to sell its entire 40% stake in De Beers to Anglo American plc , thereby increasing Anglo American's ownership of the company to 85% (with the remaining 15% owned by the Government of the Republic of Botswana). The transaction was worth £3.2 billion (US$ 5.1 billion) in cash and ended the Oppenheimer dynasty's 80-year ownership of De Beers. In 2020,
9577-502: The Orange Free State capital, Bloemfontein. French's flanking manoeuvre took a very high toll on horses and men in the blazing summer heat, with about 500 horses either dying en route or no longer fit to ride. When Cronjé became aware of French's cavalry on his left flank at Klip Drift, he concluded that the British were trying to draw him eastwards away from his prepared defences. He dispatched 900 men with guns to stop
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#17327823411879734-665: The United Nations. The initial focus of the UN's investigation was on Jonas Savimbi 's UNITA movement in Angola, which was found to have bartered uncut diamonds for weaponry despite international economic and diplomatic sanctions being in effect through United Nations Security Council Resolution 1173 . In 1999, De Beers Group stopped all outside buying of diamonds in order to guarantee the conflict-free status of their diamonds effective from 26 March 2000. In December 2000, following
9891-512: The aim of providing a range of services and equipment in the field of diamond verification. It is based in London, Antwerp and, from 2015, in Surat , India . The IIDGR works only on diamonds that meet the requirements of the United Nations' World Diamond Council Kimberley Process . In 1999, a campaign by Global Witness to highlight the role of diamonds in international conflicts led to a review by
10048-484: The amalgamation of virtually all the cavalry in the area. News of the shelling by the Boer Long Tom gun had reached Lord Roberts, whose parting words to his officers on 9 February were that "You must relieve Kimberley if it costs you half your forces." Piet Cronjé believed that Roberts would attempt to attack him in a flanking manoeuvre from the west, and that the advance would largely continue as before along
10205-704: The approach in 2008 when it broke with 44 years of direct sales to hold the diamond industry's first online international auction sale. It is now the world's leader in this kind of auction sale. De Beers employs more than 30,000 people around the globe on five continents, with more than 17,000 employees in Africa. Almost 8,000 people are employed in Botswana, around 6,200 in South Africa, nearly 2,900 in Namibia, some 1,260 in Canada and about 320 in exploration. In February 2020, De Beers reported its worst set of earnings since
10362-541: The area with a flare. The Boers besieged the town for 124 days, shelling it on most days, except Sundays. Shelling abated somewhat during the Battle of Magersfontein when the Boer siege guns were temporarily brought to bear there. Throughout the siege, Kekewich mounted numerous armed reconnaissance missions outside the town's defences, sometimes using the armoured train. Some of these engagements were fierce, with casualties on both sides, however they did not change
10519-462: The atoms form tetrahedra, with each bound to four nearest neighbors. Tetrahedra are rigid, the bonds are strong, and, of all known substances, diamond has the greatest number of atoms per unit volume, which is why it is both the hardest and the least compressible . It also has a high density, ranging from 3150 to 3530 kilograms per cubic metre (over three times the density of water) in natural diamonds and 3520 kg/m in pure diamond. In graphite,
10676-420: The atoms, they have many facets that belong to a cube , octahedron, rhombicosidodecahedron , tetrakis hexahedron , or disdyakis dodecahedron . The crystals can have rounded-off and unexpressive edges and can be elongated. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf , an opaque gum-like skin. Some diamonds contain opaque fibers. They are referred to as opaque if
10833-410: The bonds between nearest neighbors are even stronger, but the bonds between parallel adjacent planes are weak, so the planes easily slip past each other. Thus, graphite is much softer than diamond. However, the stronger bonds make graphite less flammable. Diamonds have been adopted for many uses because of the material's exceptional physical characteristics. It has the highest thermal conductivity and
10990-482: The brigade on the left to hold course for Klip Drift, while giving the enemy the false impression that he was headed for Klipkraal Drift. The whole force then wheeled left at the last minute and charged the Klip Drift crossing at full gallop. The Boers at Klip Drift, who were taken completely by surprise, left their camp and provisions behind, which French's exhausted men and horses were glad to seize. Although speed
11147-512: The carbon source is more likely carbonate rocks and organic carbon in sediments, rather than coal. Diamonds are far from evenly distributed over the Earth. A rule of thumb known as Clifford's rule states that they are almost always found in kimberlites on the oldest part of cratons , the stable cores of continents with typical ages of 2.5 billion years or more. However, there are exceptions. The Argyle diamond mine in Australia ,
11304-525: The chairman and director of Anglo-American and De Beers in December 1982. During the 20th century, De Beers used several methods to leverage its dominant position to influence the international diamond market. First, it attempted to convince independent producers to join its single channel monopoly. When that did not work, it flooded the market with diamonds similar to those of producers who refused to join in, depressing their price and undermining return for
11461-472: The closure of this office, the company was reclassified as De Beers plc in 2017, with its head office now in Jersey. It is made up of two shareholdings: Anglo American plc has an 85% shareholding and the Government of the Republic of Botswana owns 15% directly. De Beers plc is the holding company of The De Beers Group of Companies. It is involved in many parts of the diamond value chain, from mining to sales, and
11618-468: The colony, located just a few kilometres from the borders of the Boer republics of the Transvaal and Orange Free State; Cape Town was 1,041 kilometres (647 mi) away by rail, while Port Elizabeth was 780 kilometres (480 mi). The closest Boer settlements were Jacobsdal to the south and Boshof to the east. The De Beers company was concerned about the defence of Kimberley some years before
11775-436: The coloration, while pure or nearly pure diamonds are transparent and colorless. Most diamond impurities replace a carbon atom in the crystal lattice , known as a carbon flaw . The most common impurity, nitrogen, causes a slight to intense yellow coloration depending upon the type and concentration of nitrogen present. The Gemological Institute of America (GIA) classifies low saturation yellow and brown diamonds as diamonds in
11932-459: The company was bought by miner Anglo American in 2012. On 4 November 2011, Anglo American plc and CHL Holdings announced their agreement for Anglo American to acquire an incremental interest in De Beers, increasing Anglo American's 45% shareholding in the world's leading diamond company to 85%. De Beers plc was originally incorporated as De Beers Société Anonyme in 2000 in Luxembourg. Following
12089-485: The company was the sole owner of all diamond mining operations in the country. In 1889, Rhodes negotiated a strategic agreement with the London-based Diamond Syndicate, which agreed to purchase a fixed quantity of diamonds at an agreed price, thereby regulating output and maintaining prices. The agreement soon proved to be very successful – for example, during the trade slump of 1891–1892, supply
12246-435: The company's valuable mines. Rhodes personally moved into the city at the onset of the siege in order to put political pressure on the British government to divert military resources towards relieving the siege rather than more strategic war objectives. Despite being at odds with the military, Rhodes placed the full resources of the company at the disposal of the defenders, manufacturing shells , defences, an armoured train and
12403-448: The compositions of minerals are analyzed as if they were in equilibrium with mantle minerals. Finding kimberlites requires persistence, and only a small fraction contain diamonds that are commercially viable. The only major discoveries since about 1980 have been in Canada. Since existing mines have lifetimes of as little as 25 years, there could be a shortage of new diamonds in the future. Diamonds are dated by analyzing inclusions using
12560-562: The conflict. He used his position and influence to demand relief of the siege vociferously in both the press and directly of the government. However, Kekewich was a more cool-headed man, and was careful to let the authorities in Cape Town know that the situation was by no means desperate and that he would be able to hold out for several weeks. The feud between the two men escalated when the Diamond Fields Advertiser ,
12717-438: The country's war effort during World War II. During the early 1930s, the company conducted experimental work which in large part pioneered the use of diamond drills . This was highly preferable to more expensive and rarer carbons previously in use. The Free State Gold Rush was made possible in part due to this innovation, as the fields required deep drilling to reach gold-bearing reefs . In May 1955, Ernest Oppenheimer opened
12874-598: The decay of radioactive isotopes. Depending on the elemental abundances, one can look at the decay of rubidium to strontium , samarium to neodymium , uranium to lead , argon-40 to argon-39 , or rhenium to osmium . Those found in kimberlites have ages ranging from 1 to 3.5 billion years , and there can be multiple ages in the same kimberlite, indicating multiple episodes of diamond formation. The kimberlites themselves are much younger. Most of them have ages between tens of millions and 300 million years old, although there are some older exceptions (Argyle, Premier and Wawa). Thus,
13031-428: The defence as he saw fit. Kekewich decided to include the neighbouring municipality of Beaconsfield as well as the outlying suburb of Kenilworth inside the 22-kilometre (14 mi) defensive perimeter he established around the town. Rhodes sponsored the raising of a new regiment called the Kimberley Light Horse, but Lord Methuen advised Kekewich that “Rhodes is to leave Kimberley the day after I arrive. Tell him he
13188-470: The diamond crystal lattice. Plastic deformation is the cause of color in some brown and perhaps pink and red diamonds. In order of increasing rarity, yellow diamond is followed by brown, colorless, then by blue, green, black, pink, orange, purple, and red. "Black", or carbonado , diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance. Colored diamonds contain impurities or structural defects that cause
13345-506: The diamond lattice is 1.732 a /4 where a is the lattice constant, usually given in Angstrøms as a = 3.567 Å, which is 0.3567 nm. A diamond cubic lattice can be thought of as two interpenetrating face-centered cubic lattices with one displaced by 1 ⁄ 4 of the diagonal along a cubic cell, or as one lattice with two atoms associated with each lattice point. Viewed from a <1 1 1> crystallographic direction , it
13502-415: The diamond lattice, donating a hole into the valence band . Substantial conductivity is commonly observed in nominally undoped diamond grown by chemical vapor deposition . This conductivity is associated with hydrogen -related species adsorbed at the surface, and it can be removed by annealing or other surface treatments. Thin needles of diamond can be made to vary their electronic band gap from
13659-407: The diamonds' surface cannot be wet by water, but can be easily wet and stuck by oil. This property can be utilized to extract diamonds using oil when making synthetic diamonds. However, when diamond surfaces are chemically modified with certain ions, they are expected to become so hydrophilic that they can stabilize multiple layers of water ice at human body temperature . The surface of diamonds
13816-495: The famous advertising slogan, 'A Diamond is Forever', in 1947. In 2000, Advertising Age magazine named 'A Diamond is Forever' the best advertising slogan of the 20th century. The slogan may have inspired the James Bond book, film and song title Diamonds Are Forever . Other successful campaigns include the ' eternity ring ' (meant as a symbol of continuing affection and appreciation), the 'trilogy ring' (meant to represent
13973-449: The fibers grow from a clear substrate or fibrous if they occupy the entire crystal. Their colors range from yellow to green or gray, sometimes with cloud-like white to gray impurities. Their most common shape is cuboidal, but they can also form octahedra, dodecahedra, macles, or combined shapes. The structure is the result of numerous impurities with sizes between 1 and 5 microns. These diamonds probably formed in kimberlite magma and sampled
14130-429: The final states of the siege to eating horse meat. Vegetables could not be grown easily because of a shortage of water. The scarcity of vegetables took the hardest toll on the poorest people, notably the 15,000-strong indigenous population; a local doctor suggested that they eat aloe leaves to avoid contracting scurvy , while Rhodes organised a soup kitchen . On 25 November, the British garrison launched an attack on
14287-484: The garrison to capitulate. Engineers of the De Beers company manufactured a one-off gun named Long Cecil ; however the Boers soon countered with a much larger siege gun that terrified the residents, forcing many to take shelter in the Kimberley Mine . The British military had to change its strategy for the war as public opinion demanded that the sieges of Kimberley, Ladysmith and Mafeking be relieved before
14444-408: The hardness and transparency of diamond, are the reasons that diamond anvil cells are the main tool for high pressure experiments. These anvils have reached pressures of 600 GPa . Much higher pressures may be possible with nanocrystalline diamonds. Usually, attempting to deform bulk diamond crystal by tension or bending results in brittle fracture. However, when single crystalline diamond
14601-455: The highest sound velocity. It has low adhesion and friction, and its coefficient of thermal expansion is extremely low. Its optical transparency extends from the far infrared to the deep ultraviolet and it has high optical dispersion . It also has high electrical resistance. It is chemically inert, not reacting with most corrosive substances, and has excellent biological compatibility. The equilibrium pressure and temperature conditions for
14758-454: The horses were depleted. At first light, the cavalry headed towards the Boer dust clouds; soon they were overlooking a whole valley full of Boers, with cattle, 400 wagons and women and children in tow. The surprise was complete when the British started shelling the Boer column just as it started crossing the Modder River at Paardeberg Drift, causing considerable confusion and panic. Cronjé elected to sit tight rather than escape, giving French
14915-423: The kimberlites formed independently of the diamonds and served only to transport them to the surface. Kimberlites are also much younger than the cratons they have erupted through. The reason for the lack of older kimberlites is unknown, but it suggests there was some change in mantle chemistry or tectonics. No kimberlite has erupted in human history. Most gem-quality diamonds come from depths of 150–250 km in
15072-474: The largest producer of diamonds by weight in the world, is located in a mobile belt , also known as an orogenic belt , a weaker zone surrounding the central craton that has undergone compressional tectonics. Instead of kimberlite , the host rock is lamproite . Lamproites with diamonds that are not economically viable are also found in the United States, India, and Australia. In addition, diamonds in
15229-406: The local newspaper which was under Rhodes's control, ignored the military censor and printed information that compromised the military. Kekewich obtained permission from his superior to place Rhodes under arrest if necessary. The food and water supply was managed closely by the military authorities. Rationing was imposed as the food supply dwindled, with the inhabitants eventually resorting in
15386-467: The macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond has a cleavage plane and is therefore more fragile in some orientations than others. Diamond cutters use this attribute to cleave some stones before faceting them. "Impact toughness" is one of the main indexes to measure the quality of synthetic industrial diamonds. Diamond has compressive yield strength of 130–140 GPa. This exceptionally high value, along with
15543-693: The manufacturing process from the mine to the retailer in order to ensure their quality and conflict-free status. In 2019, they launched their own end-to-end traceability platform called Tracr to enable all diamonds to be identified and traced as they move from the mine to the store. Signet and the Russian-based Alrosa are using the technology. In August 2017, De Beers partnered with the Stanford Graduate School of Business to accelerate business ventures to market in Botswana, Namibia, and South Africa. As part of two programs,
15700-405: The meat. The Boer commander, Commandant Cornelius Wessels, presented Kekewich with an ultimatum on 4 November, demanding the town's surrender. Kekewich replied the same day, stating: “...you are hereby invited to effect the occupation of this town as an operation of war by the employment of the military forces under your command”. When the siege of Kimberley itself began in earnest on 6 November,
15857-591: The melting point of diamond increases slowly with increasing pressure; but at pressures of hundreds of GPa, it decreases. At high pressures, silicon and germanium have a BC8 body-centered cubic crystal structure, and a similar structure is predicted for carbon at high pressures. At 0 K , the transition is predicted to occur at 1100 GPa . Results published in an article in the scientific journal Nature Physics in 2010 suggest that, at ultra-high pressures and temperatures (about 10 million atmospheres or 1 TPa and 50,000 °C), diamond melts into
16014-579: The melts to carry diamonds to the surface before they dissolve. Kimberlite pipes can be difficult to find. They weather quickly (within a few years after exposure) and tend to have lower topographic relief than surrounding rock. If they are visible in outcrops, the diamonds are never visible because they are so rare. In any case, kimberlites are often covered with vegetation, sediments, soils, or lakes. In modern searches, geophysical methods such as aeromagnetic surveys , electrical resistivity , and gravimetry , help identify promising regions to explore. This
16171-447: The middle. As waves of horses galloped forward, the Boers poured down fire from the two sides. However, the speed of the attack, screened by a massive cloud of dust, proved successful and the Boer force was defeated. British casualties during this day's fighting were five dead and 10 wounded, with roughly 70 horses lost through exhaustion. However, the route to Kimberley was open; by that evening, General French and his men passed through
16328-415: The military felt that Rhodes proved to be more of a hindrance as he did not co-operate fully with them; civil and military authorities were not always working together, especially after the death of the second in command of the garrison, Major Scott-Turner. The military took the following view of Rhodes: Rhodes had come into his own Kimberley and for the first time he was not master in it. He found himself
16485-479: The mining activities, moved into the town at the onset of the siege. His presence was controversial, as his involvement in the Jameson Raid made him one of the primary protagonists behind war breaking out. Rhodes was in constant disagreement with the military, but he was nonetheless instrumental in organising the defence of the town. The Boers shelled the town with their superior artillery in an attempt to force
16642-426: The morning. Thirty-three Boers were captured at the cost of four killed. Scott-Turner tried to repeat the successful raid three days later, but it was a disaster for the British the second time round, with Scott-Turner among those killed. The engineers of Rhodes's company, under Chief Mechanical Engineer George Labram, were instrumental in the defence of the town. They manufactured fortifications, an armoured train,
16799-520: The new headquarters which combined the operations of Anglo American and the De Beers group. After Ernest died in November 1957, operation of Anglo and De Beers were passed on to his son, Harry Oppenheimer . Under Harry, the company expanded to several different countries around the globe, including Canada, Australia , Malaysia , Portugal , Zambia , and Tanzania . In South Africa, Harry opposed apartheid , arguing that it hindered economic growth. Despite this, De Beers has been criticized for profiting from
16956-469: The normal 5.6 eV to near zero by selective mechanical deformation. High-purity diamond wafers 5 cm in diameter exhibit perfect resistance in one direction and perfect conductance in the other, creating the possibility of using them for quantum data storage. The material contains only 3 parts per million of nitrogen. The diamond was grown on a stepped substrate, which eliminated cracking. Diamonds are naturally lipophilic and hydrophobic , which means
17113-452: The opportunity to summon reinforcements before the Boers realised how small and depleted the force was that was harassing them. The Battle of Paardeberg ensued over the next week, resulting in the defeat of Cronjé, but at the expense of a considerable amount of British blood. On 17 February, Kekewich was promoted to the rank of full colonel while French was promoted to major general . A number of medals were issued to combatants, notably
17270-492: The outbreak of the war, particularly its vulnerability to attack from the neighbouring Orange Free State. In 1896, an arms depot was formed, a plan of defence sent to the authorities and a local defence force set up. As it began to look more likely that war would break out, the nervous citizens of Kimberley appealed to the premier of the Cape Colony, William Philip Schreiner , for additional protection, but he did not believe
17427-575: The partnership is set to help teach early entrepreneurs how to commercialize their business ideas. The partnership is a three-year, $ 3 million deal. In September 2017, De Beers partnered with UN Women to help the advancement of women within the company and the countries it operates in. In 2018, the two entities launched a program to support 500 women micro-entrepreneurs in Blouberg and Musina communities, near De Beers's Venetia diamond mine . In May 2018, De Beers's group company Element Six launched
17584-469: The past, present, and future of a relationship) and the 'right hand ring' (meant to be bought and worn by women as a symbol of independence). De Beers ran television advertisements featuring silhouettes of people wearing diamonds, set to the music of ' Palladio ' by Karl Jenkins . The campaign, titled "Shadows and Lights" first ran in the first quarter of 1993. The song would later inspire a compilation album, Diamond Music , released in 1996, which features
17741-620: The presence of natural minerals and oxides. The clarity scale grades the diamond based on the color, size, location of impurity and quantity of clarity visible under 10x magnification. Inclusions in diamond can be extracted by optical methods. The process is to take pre-enhancement images, identifying the inclusion removal part and finally removing the diamond facets and noises. Between 25% and 35% of natural diamonds exhibit some degree of fluorescence when examined under invisible long-wave ultraviolet light or higher energy radiation sources such as X-rays and lasers. Incandescent lighting will not cause
17898-466: The railway line. With this mind, Roberts ordered the Highland Brigade 20 miles (32 km) west to Koedoesberg, thereby encouraging Cronjé's forces to believe that the attack would occur there. However, the bulk of the force initially headed south to Graspan , then east deep into the Orange Free State with the cavalry division guarding the British right flank by securing drifts across
18055-469: The recently abandoned Boer lines, and relieved the town of Kimberley after some initial difficulty in convincing the defenders via heliograph that they were not Boers. The cavalry had covered 120 miles (190 km) in four days at the height of summer to reach the town. When French arrived in town, he snubbed Kekewich, the local military authority, by presenting himself to Rhodes instead. French's men did not have much opportunity to relax when they reached
18212-588: The recommendations of the Fowler Report , the UN adopted the landmark General Assembly Resolution A/RES/55/56 supporting the creation of an international certification scheme for rough diamonds. By November 2002, negotiations between governments, the international diamond industry, led by De Beers, and civil society organisations resulted in the creation of the Kimberley Process Certification Scheme (KPCS), which sets out
18369-685: The requirements for controlling rough diamond production and trade and became effective in 2003. De Beers states that 100% of the diamonds it now sells are conflict-free and that all De Beers diamonds are purchased in compliance with national law, the Kimberley Process Certification Scheme and its own Diamond Best Practice Principles. The Kimberley process has helped restore the reputation of the industry, as well as eliminating sources of excess supply. In 2018, De Beers used blockchain technology to successfully track 100 high-value diamonds. The diamonds were tracked through
18526-544: The resistant. It also purchased and stockpiled diamonds produced by other manufacturers as well as surplus diamonds in order to control prices by limiting supply . Finally, it bought diamonds when prices fell considerably naturally, to constrict supply and drive their value back up, such as during the Great Depression. In 2000, the De Beers business model changed because of factors such as the decision by producers in Canada and Australia to distribute diamonds outside
18683-543: The site of the Big Hole and the De Beers mine, two successful diamond mines. Their name, which was given to one of the mines, subsequently became associated with the company. Cecil Rhodes , the founder of the British South Africa Company , got his start by renting water pumps to miners during the diamond rush that started in 1869, when an 83.5 carat diamond called the ' Star of South Africa '
18840-533: The situation favoured an attack. The Boers were in control of the railway from the Orange River to Mafeking, while arms and ammunition were in short supply in Kimberley. On 7 November, the Boers started shelling the town. Communication with the outside world was not seriously impeded however. The Boer strategy was not to attack the town in a full battle, but rather to wait for the defenders to capitulate, all
18997-529: The size of the resulting indentation, a Vickers hardness value for the material can be determined. Diamond's great hardness relative to other materials has been known since antiquity, and is the source of its name. This does not mean that it is infinitely hard, indestructible, or unscratchable. Indeed, diamonds can be scratched by other diamonds and worn down over time even by softer materials, such as vinyl phonograph records . Diamond hardness depends on its purity, crystalline perfection, and orientation: hardness
19154-419: The stable phase of carbon is graphite, but diamond is metastable and its rate of conversion to graphite is negligible. However, at temperatures above about 4500 K , diamond rapidly converts to graphite. Rapid conversion of graphite to diamond requires pressures well above the equilibrium line: at 2000 K , a pressure of 35 GPa is needed. Above the graphite–diamond–liquid carbon triple point,
19311-554: The start of the 21st century, De Beers controlled 80% to 85% of rough diamond distribution and was considered a monopoly . By 2000, the company's control of the world diamond supply decreased to 63%. The company was founded in 1888 by British businessman Cecil Rhodes , who was financed by the South African diamond magnate Alfred Beit and the London-based N M Rothschild & Sons bank. In 1926, Ernest Oppenheimer ,
19468-479: The status quo, as terrified residents were no longer able to find sanctuary anywhere at ground level. Rhodes published a notice inviting people to take shelter in the Kimberley Mine in order to avoid its lethal shelling. Fortunately for the defenders, the gun did not use smokeless powder , so observers were able to give residents up to 17 seconds warning to take cover when a shell was incoming. Labram
19625-422: The status quo. In January 1900, the local Boer command passed from Commandant Wessels to General Ignatius Stephanus Ferreira. The British commander-in-chief in South Africa, General Sir Redvers Buller initially planned to march with a single large force on the Boer capitals of Bloemfontein and Pretoria . However public opinion demanded relief of the sieges of Kimberley, Ladysmith and Mafeking — pressure that
19782-473: The stones are produced in Gresham, Oregon , a $ 94 million facility using the region's cheap electricity, which opened in 2018 with the capacity for 500,000 rough carats of diamonds per year. Mining in Botswana takes place through the mining company Debswana , a 50–50 joint venture with the Government of the Republic of Botswana. It operates four mines – Jwaneng, Orapa, Letlhakane and Damtshaa, though Damtshaa
19939-524: The surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites . Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gases by chemical vapor deposition (CVD). Imitation diamonds can also be made out of materials such as cubic zirconia and silicon carbide . Natural, synthetic, and imitation diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. Diamond
20096-413: The system during the apartheid period. By 1973, Anglo and De Beers accounted for 10 percent of South Africa's gross national product and 30 percent of the country's exports. Throughout the 1960s and 1970s, De Beers attempted to secretly enter the United States' diamond market, being forced to divest its American assets in 1975 to avoid the risk of violating anti-trust laws. Harry Oppenheimer stepped down as
20253-411: The time wearing them down with shelling. The defenders tried to send the large contingent of migrant native labourers that was working in the mines home, but twice the Boers drove them back into the town in an apparent attempt to put pressure on the limited food and water supply. Rhodes had his own agenda, which differed from the greater war goal of redressing wrongs in the Transvaal that had triggered
20410-607: The town at Riverton Road, then shut off the primary water supply at Riverton on the Vaal River . For the first time, water in the mines became more precious than the diamonds in them. On 14 October the Boers cut the telephone line to the Cape. Heliograph and dispatch riders consequently had to make hazardous journeys through Boer lines to the Orange River and then to Cape Town and Port Elizabeth. On 15 October, martial law
20567-653: The town guard and raise the Diamond Fields Artillery. Three days later, the town was placed under the command of Colonel Robert Kekewich of the 1st Battalion, Loyal Regiment (North Lancashire) , and secured against a coup de main , but not against sustained siege. Colonel Kekewich's troops consisted of four companies of the Loyal North Lancashire Regiment, some Royal Engineers , six RML 2.5-inch mountain guns and two machine guns. Also at his disposal were 120 men of
20724-553: The town itself was relieved. Prior to the onset of the Second Boer War , Kimberley was the second-biggest city in the Cape Colony , and vibrant and prosperous as the centre of diamond mining operations of the De Beers Mining Company, who supplied 90% of the world's diamonds. The town had a population of 40,000, of which 25,000 were white. It was one of a handful of British outposts in the far north east of
20881-431: The town to be under serious threat and declined to arm it further. His reply to an appeal for arms in September 1899 stated: “There is no reason whatever for apprehending that Kimberley is or will be in any danger of attack and your fears are therefore groundless.” The town next appealed to the high commissioner, this time with more success. On 4 October 1899, Major Scott-Turner was permitted to summon volunteers to join
21038-510: The town, as they were roused during their first night in the town first to make yet another dash to try to capture the Long Tom gun and, in the early hours of 17 February, to cut off Cronjé's main force, who had abandoned Magersfontein and were heading east towards Bloemfontein along the Modder River. Kitchener directed French to cut off the Boers' escape; of French's original strength of 5,000, only 1,200 of his cavalrymen were still fit, while
21195-541: The town, were unable to reach it. Field Marshal Lord Roberts replaced Buller as British Commander-in-Chief in South Africa in January 1900. Within a month Roberts assembled 30,000 infantry, 7,501 cavalry and 3,600 mounted infantry, together with 120 guns, in the area between the Orange and Modder Rivers. The largest British mounted division ever assembled was created under the command of Major-General John French through
21352-566: The town. The Boers countered on 7 February with a much heavier 100-pounder named "Long Tom" ; it had been disabled by British saboteurs at Ladysmith , before being repaired at Pretoria, and brought to Kimberley. In addition to having larger shells than any of the siege guns used up to that point, its longer range meant that it could also target any location in Kimberley. The town's inhabitants had become accustomed to shelling by smaller guns and were to some extent able to take shelter and to carry on their daily lives. The new gun immediately changed
21509-421: The town. However, Methuen's advance ground to a halt after the Boers inflicted heavy casualties on his force at the Battle of Modder River and defeated him resoundingly at the Battle of Magersfontein . These, and other defeats elsewhere, came to be called " Black Week " by the British. Thus, for two of the four months of the siege, the 10,000 British troops at Modder River who were within 12 miles (19 km) of
21666-454: The volatiles. Diamonds can also form polycrystalline aggregates. There have been attempts to classify them into groups with names such as boart , ballas , stewartite, and framesite, but there is no widely accepted set of criteria. Carbonado, a type in which the diamond grains were sintered (fused without melting by the application of heat and pressure), is black in color and tougher than single crystal diamond. It has never been observed in
21823-635: The war between Kimberley and Mafeking at Kraaipan by Boers under the command of fighting general De la Rey , the hero of the western Transvaal. On 12 October, the Jacobsdal Commando severed the railway line at the bridge over the Modder River south of Kimberley, whereafter the Boers entrenched themselves in the hills at Spytfontein. Meanwhile, the Boshof Commando severed the railway line 16 kilometres (10 mi) north of
21980-544: The world's diamond production. Ernest Oppenheimer took over the chairmanship of the company in 1929, after buying shares and being appointed to the board in 1926. Oppenheimer was very concerned about the discovery of diamonds in 1908 in German South West Africa , fearing that the increased supply would swamp the market and force prices down. Former CIA chief Admiral Stansfield Turner claimed that De Beers restricted US access to industrial diamonds needed for
22137-430: The world's largest diamond deposit, estimated at trillions of carats, and formed by an asteroid impact. A common misconception is that diamonds form from highly compressed coal . Coal is formed from buried prehistoric plants, and most diamonds that have been dated are far older than the first land plants . It is possible that diamonds can form from coal in subduction zones , but diamonds formed in this way are rare, and
22294-441: The world's rough diamonds by value. There are two main types of customers for rough diamonds – Sightholders and Accredited Buyers. Sightholders have a term contract. Accredited Buyer status, introduced in 2015, allows companies that are not traditional Sightholders to access diamonds that were not allocated to existing Sightholders. De Beers also sells about 10% of its rough diamonds through online auction sales. The company pioneered
22451-401: Was a calculated move to raise the political stakes and thereby force the British government to divert war resources to lifting the siege on his mining operation. Since most of the resources in the garrison were owned by De Beers, Rhodes inevitably became an important factor in the defence organised by Colonel Robert Kekewich. As head of the mining company that owned most of the assets in the town,
22608-531: Was accused of not releasing industrial diamonds for the US war effort during World War II. In 2011, Anglo American took control of De Beers after buying the Oppenheimers' family stake of 40% for US$ 5.1 billion (£3.2 billion) and increasing its stake to 85%, ending the 80-year Oppenheimer control of the company. In May 2024, Anglo American announced its intention to spin off or sell De Beers. The name 'De Beers'
22765-480: Was appointed the local agent for the powerful London Syndicate, rising to the position of mayor of Kimberley within 10 years. He understood the core principle that underpinned De Beers's success, stating in 1910 that "common sense tells us that the only way to increase the value of diamonds is to make them scarce, that is to reduce production". During World War I, the Premier Mine was finally absorbed into De Beers. When Rhodes died in 1902, De Beers controlled 90% of
22922-469: Was attributable in part to Rhodes's presence in Kimberley and lobbying in London. Buller therefore had to change his plans and divide his forces: Lord Methuen was sent north by the War Office in December 1899 with the objective of relieving Kimberley and Mafeking, while Buller himself went to Natal. On 1 December 1899, communications were established between Methuen's relief column and the defenders in
23079-399: Was declared in the town. The cattle that usually grazed on the outskirts of the town presented a problem; if they were left, they would be lost to the Boers, but if they were slaughtered, the meat would perish quickly in the summer heat. The De Beers chief engineer, George Labram , provided a solution by building an industrial refrigeration plant underground in the Kimberley mine to preserve
23236-581: Was derived from the two Dutch settlers , brothers Diederik Arnoldus de Beer (1825–1878) and Johannes Nicolaas de Beer (1830–1883), who owned a South African farm named Vooruitzicht ( Dutch for "prospect" or "outlook") near Zandfontein in the Boshof District of Orange Free State . After they discovered diamonds on their land, the increasing demands of the British government forced them to sell their farm on 31 July 1871 to merchant Alfred Johnson Ebden (1820–1908) for £6,600. Vooruitzicht would become
23393-526: Was established in 2001 as a 50:50 joint venture between The De Beers Group of Companies and LVMH , the French luxury goods company. The first De Beers boutique opened in 2002 on London's Old Bond Street as the brand's flagship store. Since then, stores have opened in various cities around the world. In March 2017, The De Beers Group of Companies acquired LVMH's 50% shareholding in DBDJ and new name De Beers Jewellers
23550-508: Was found at Hopetown near the Orange River in South Africa. He invested the profits of this operation into buying up claims of small mining operators, with his operations soon expanding into a separate mining company. He soon secured funding from the Rothschild family , who would finance his business expansion. De Beers Consolidated Mines was formed in 1888 by the merger of the companies of Barney Barnato and Cecil Rhodes, by which time
23707-427: Was ill-prepared, but the defenders organised an energetic and effective improvised defence that was able to prevent it from being taken. Outside Kimberley, the Boers treated the occupied territory as part of one of the republics, appointing a 'landdrost' (magistrate) and changing the name of the neighbouring town of Barkly West to Nieu Boshof. Cecil Rhodes , who had made his fortune in the town, and who controlled all
23864-475: Was important, the cavalry had to wait for the infantry to catch up to secure the lines of communication before moving forward to relieve Kimberley. The cavalry's route had taken them deep inside the Free State over Cronjé's line of communication , thereby cutting off any Boer forces who did not immediately fall back. Meanwhile, Roberts led the main force in an easterly direction with the objective of capturing
24021-403: Was launched in 2008 as one of the two diamond brands from The De Beers Group of Companies. According to the company website, "Each Forevermark diamond is inscribed with a promise: that it is beautiful, rare and responsibly sourced." Forevermark diamonds are inscribed with an icon and unique identification number, albeit invisibly to the naked eye: the Forevermark inscription is 1 ⁄ 20 th of
24178-416: Was put on care and maintenance in 2015. In Namibia, mining is carried out through Namdeb Holdings , a 50–50 joint venture with the Government of the Republic of Namibia. Namdeb Holdings is made up of Debmarine Namibia (covering offshore mining) and Namdeb Diamond Corporation (land-based coastal mining). For offshore mining, motor vessels are used, including the 12,000-tonne, 113-metre-long SS Nujoma, built at
24335-417: Was simply curtailed to maintain the price. Rhodes was concerned about the break-up of the new monopoly, stating to shareholders in 1896 that the company's "only risk is the sudden discovery of new mines, which human nature will work recklessly to the detriment of us all". The Second Boer War proved to be a challenging time for the company. Kimberley was besieged as soon as war broke out, thereby threatening
24492-401: Was the most notable civilian casualty, when he was killed within a week of the end of the siege, ironically by a Boer shell from the Long Tom gun brought to counter his own gun. Kekewich arranged a full military funeral for him, which was well attended, but took place after dark for safety reasons; the procession was targeted by Boer shelling with the help of a traitor inside the town who lit
24649-424: Was unveiled. De Beers Ventures De Beers Ventures was established by De Beers Group in June 2017 to consider minority stake investments in start-ups and growth companies that could be of benefit to De Beers Group or the broader diamond sector. The International Institute of Diamond Grading & Research The International Institute of Diamond Grading & Research (IIDGR) was set up by De Beers in 2008, with
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