I walk in a commercial area with low buildings like strip malls. Although there is no retail, various vendors are side by side in long rows. One of them appears to be a diamond wholesaler. The only diamond I have ever owned is an engagement ring, and it was a very small diamond — maybe ¼ of a carat. I never even had diamond earrings. They were all rhinestones. I had a friend who was very disappointed when her husband gave her a cubic zirconia ring because it was not a real diamond. I just watched an episode of “The Big Bang Theory” where Sheldon gives Amy diamonds to compensate for not being congratulatory when she makes an important scientific discovery. She is about to put down his choice of a gift as frivolous until she finds out it is a tiara. Then she is thrilled to be a princess. I guess everyone has their favorite form of diamonds.
According to Wikipedia, diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At room temperature and pressure, another solid form of carbon known as graphite is the chemically stable form of carbon, but diamond almost never converts to it.
Diamond has the highest hardness and thermal conductivity of any natural material, properties that are utilized 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 the Earth.
Because the arrangement of atoms in diamonds are extremely rigid, few types of impurity can contaminate them — two exceptions being boron and nitrogen. Small numbers of defects or impurities — about one per million of lattice atoms — color diamonds blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange or red. Diamonds also have relatively high optical dispersion — ability to disperse light of different colors.
Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 93 and 155 miles in the Earth's mantle, although a few have come from as deep as 500 miles. Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently — tens to hundreds of million years ago — they were carried to 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 gas by chemical vapor deposition. 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.
History
After the 1797 discovery that diamond was pure carbon, many attempts were made to convert various cheap forms of carbon into diamonds. The earliest successes were reported by James Ballantyne Hanay in 1879 and by Ferdinand Frédéric Henri Mossian in 1893. Their method involved heating charcoal at up to 3500 °C with iron inside a carbon crucible in a furnace. Whereas Hannay used a flame-heated tube, Moissan applied his newly developed electric arc furnace, in which an electric arc was struck between carbon rods inside blocks of lime. The molten iron was then rapidly cooled by immersion in water. The contraction generated by the cooling supposedly produced the high pressure required to transform graphite into diamonds. Moissan published his work in a series of articles in the 1890s.
Many other scientists tried to replicate his experiments. Sir William Crookes claimed success in 1909. Otto Ruff claimed in 1917 to have produced diamonds up to 7 mm in diameter, but later retracted his statement. In 1926, Dr. J Willard Hershey of McPherson College replicated Moissan's and Ruff's experiments, producing a synthetic diamond; that specimen is on display at the McPherson Museum in Kansas. Despite the claims of Moissan, Ruff and Hershey, other experimenters were unable to reproduce their synthesis.
The most definitive replication attempts were performed by Sir Charles Algernon Parsons. A prominent scientist and engineer known for his invention of the steam turbine, he spent about 40 years (1882–1922) and a considerable part of his fortune trying to reproduce the experiments of Moissan and Hannay, but also adapted processes of his own. Parsons was known for his painstakingly accurate approach and methodical record keeping; all his resulting samples were preserved for further analysis by an independent party. He wrote many articles — some of the earliest on high pressure/high temperature diamonds — in which he claimed to have produced small diamonds. However, in 1928, he authorized Dr. C. H. Desch to publish an article in which he stated his belief that no synthetic diamonds — including those of Moissan and others — had been produced up to that date. He suggested that most diamonds that had been produced up to that point were likely synthetic spinel.
GE diamond project
In 1941, an agreement was made between the General Electric, Norton and Carborundum companies to further develop diamond synthesis. They were able to heat carbon to about 3,000 °C (5,430 °F) under a pressure of 510,000 psi for a few seconds. Soon thereafter, World War II interrupted the project. It was resumed in 1951 at the Schenectady Laboratories of GE, and a high-pressure diamond group was formed with Francis P. Bundy and H. M. Strong. Tracy Hall and others joined the project later.
The Schenectady group improved on the anvils designed by Percy Bridgman, who received a Nobel Prize for his work in 1946. Bundy and Strong made the first improvements, then more were made by Hall. The GE team used tungsten carbide anvils within a hydraulic press to squeeze the carbonaceous sample held in a catlinite container, the finished grit being squeezed out of the container into a gasket. The team recorded diamond synthesis on one occasion, but the experiment could not be reproduced because of uncertain synthesis conditions, and the diamond was later shown to have been a natural diamond used as a seed.
Hall achieved the first commercially successful synthesis of diamond on December 16, 1954, and it was announced on February 15, 1955. His breakthrough was using a "belt" press, which was capable of producing pressures above 1,500,000 psi and temperatures above 3,630 °F. The press used a pyrophyllite container in which graphite was dissolved within molten nickel, cobalt or iron. Those metals acted as a "solvent-catalyst," which both dissolved carbon and accelerated its conversion into diamond. The largest diamond he produced was 0.15 mm across; it was too small and visually imperfect for jewelry, but usable in industrial abrasives. Hall's co-workers were able to replicate his work, and the discovery was published in the major journal Nature. He was the first person to grow a synthetic diamond with a reproducible, verifiable and well-documented process. He left GE in 1955, and three years later developed a new apparatus for the synthesis of diamond — a tetrahedral press with four anvils — to avoid violating a U.S. Department of Commerce secrecy order on the GE patent applications.
Later developments
An independent diamond synthesis was achieved on February 16, 1953, in Stockholm by ASEA — Allmänna Svenska Elektriska Aktiebolaget, one of Sweden's major electrical manufacturing companies. Starting in 1949, ASEA employed a team of five scientists and engineers as part of a top-secret, diamond-making project code-named QUINTUS. The team used a bulky split-sphere apparatus designed by Baltzar von Platen and Anders Kämpe. Pressure was maintained within the device at an estimated 8.4 gigapascal for an hour. A few small diamonds were produced, but not of gem quality or size. The work was not reported until the 1980s. During the 1980s, a new competitor emerged in Korea, a company named Iljin Diamond; it was followed by hundreds of Chinese enterprises. Iljin Diamond allegedly accomplished diamond synthesis in 1988 by misappropriating trade secrets from GE via a Korean former GE employee.
Synthetic, gem-quality diamond crystals were first produced in 1970 by GE, then reported in 1971. The first successes used a pyrophyllite tube seeded at each end with thin pieces of diamond. The graphite feed material was placed in the center and the metal solvent — nickel — between the graphite and the seeds. The container was heated and the pressure was raised to about 5.5 GPa. The crystals grow as they flow from the center to the ends of the tube and extending the length of the process produces larger crystals. Initially, a week-long growth process produced gem-quality stones of around 1 carat, and the process conditions had to be as stable as possible. The graphite feed was soon replaced by diamond grit because that allowed much better control of the shape of the final crystal.
Although the GE stones and natural diamonds were chemically identical, their physical properties were not the same. The colorless stones produced strong fluorescence and phosphorescence under short-wavelength ultraviolet light, but were inert under long-wave UV. Among natural diamonds, only the rarer blue gems exhibit these properties. Unlike natural diamonds, all the GE stones showed strong yellow fluorescence under X-rays. The De Beers Diamond Research Laboratory has grown stones of up to 25 carats for research purposes. Stable high-pressure/high-temperature conditions were kept for six weeks to grow high-quality diamonds of this size. For economic reasons, the growth of most synthetic diamonds is terminated when they reach a mass of 1 carat to 1.5 carats.
In the 1950s, research started in the Soviet Union and the U.S. on the growth of diamond by pyrolysis of hydrocarbon gases at the relatively low temperature of 800 °C. This low-pressure process is known as chemical vapor deposition. William G. Eversole reportedly achieved vapor deposition of diamond over diamond substrate in 1953, but it was not reported until 1962. Diamond film deposition was independently reproduced by Angus and coworkers in 1968 and by Deryagin and Fedoseev in 1970. Whereas Eversole and Angus used large, expensive, single-crystal diamonds as substrates, Deryagin and Fedoseev succeeded in making diamond films on non-diamond materials — silicon and metals — which led to massive research on inexpensive diamond coatings in the 1980s.
Color
Diamonds have a wide bandgap of 5.5 electronvolts corresponding to the deep ultraviolet wavelength of 225 nanometers. This means that pure diamonds should transmit visible light and appear as clear colorless crystals. Colors in diamonds originate from lattice defects and impurities. The diamond crystal lattice is exceptionally strong, and only atoms of nitrogen, boron and hydrogen can be introduced into diamonds during the growth at significant concentrations. Transition metals nickel and cobalt — which are commonly used for growth of synthetic diamonds by high-pressure high-temperature techniques — have been detected in diamonds as individual atoms; the maximum concentration is 0.01% for nickel and even less for cobalt. Virtually any element can be introduced to diamonds 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. Colors in diamonds have two additional sources: irradiation — usually by alpha particles — that causes the color in green diamonds and plastic deformation of 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 diamonds are 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 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 classifies low saturation yellow and brown diamonds as diamonds in the normal color range and applies a grading scale from "D" (colorless) to "Z" (light yellow). Diamonds of a different color, such as 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 $24 million at a Christie's auction. In May 2009, a 7.03-carat blue diamond fetched the highest price per carat ever paid for a diamond when it was sold at auction for $9.5 million. That record was, however, beaten the same year: a 5-carat vivid pink diamond was sold for $10.8 million in Hong Kong on December 1, 2009.
Hope Diamond
The Hope Diamond is one of the most famous jewels in the world, with ownership records dating back almost four centuries. Its much-admired rare blue color is due to trace amounts of boron atoms. Weighing 45.52 carats, its exceptional size has revealed new findings about the formation of gemstones.
The stone was originated from the Kollur Mine, Golconda Sultanate — now in India. The stone is one from the world-famous Golconda diamonds. Earliest records show the stone was purchased in 1666 by French gem merchant Jean-Baptiste Tavernier as the Tavernier Blue. The Tavernier Blue was cut and yielded the French Blue, which Tavernier sold to King Louis XIV in 1668. Stolen in 1791, it was recut, with the largest section acquiring its "Hope" name when it appeared in the catalogue of a gem collection owned by a London banking family called Hope in 1839.
After going through numerous owners, it was sold to Washington socialite Evalyn Walsh McLean, who was often seen wearing it. It was purchased in 1949 by New York gem merchant Harry Winston, who toured it for a number of years before giving it to the National Museum of Natural History of the United States in 1958, where it has since remained on permanent exhibition.
Cutting
Mined rough diamonds are converted into gems through a multistep process called "cutting." Diamonds are extremely hard, but also brittle and can be split up by a single blow. Therefore, diamond cutting is traditionally considered as a delicate procedure requiring skills, scientific knowledge, tools and experience. Its final goal is to produce a faceted jewel where the specific angles between the facets would optimize the diamond luster, that is dispersion of white light, whereas the number and area of facets would determine the weight of the final product. The weight reduction upon cutting is significant and can be of the order of 50%. Several possible shapes are considered, but the final decision is often determined not only by scientific, but also practical considerations. For example, the diamond might be intended for display or for wear, in a ring or a necklace, singled or surrounded by other gems of certain color and shape. Some of them may be considered as classical, such as round, pear marquise, oval, harts and arrows diamonds, etc. Some of them are special, produced by certain companies, for example, Phoenix, Cushion, Sole Mio diamonds, etc.
The most time-consuming part of the cutting is the preliminary analysis of the rough stone. It needs to address a large number of issues, bears much responsibility, and therefore can last years in case of unique diamonds. The following issues are considered:
- The hardness of diamond and its ability to cleave strongly depend on the crystal orientation. Therefore, the crystallographic structure of the diamond to be cut is analyzed using X-ray diffraction to choose the optimal cutting directions.
- Most diamonds contain visible non-diamond inclusions and crystal flaws. The cutter has to decide which flaws are to be removed by the cutting and which could be kept.
- The diamond can be split by a single, well-calculated blow of a hammer to a pointed tool, which is quick, but risky. Alternatively, it can be cut with a diamond saw, which is a more reliable but tedious procedure.
Mining
Approximately 130,000,000 carats of diamonds are mined annually, with a total value of nearly $9 billion, and about 220,000 lbs are synthesized annually.
Roughly 49% of diamonds originate from Central and Southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil and Australia. They are mined from kimberlite and lamproite volcanic pipes, which can bring diamond crystals, originating from deep within the Earth where high pressures and temperatures enable them to form, to the surface. The mining and distribution of natural diamonds are subjects of frequent controversy such as concerns over the sale of blood diamonds or conflict diamonds by African paramilitary groups. The diamond supply chain is controlled by a limited number of powerful businesses and is also highly concentrated in a small number of locations around the world.
Only a very small fraction of the diamond ore consists of actual diamonds. The ore is crushed, during which care is required not to destroy larger diamonds, and then sorted by density. Today, diamonds are located in the diamond-rich density fraction with the help of X-ray fluorescence, after which the final sorting steps are done by hand. Before the use of X-rays became commonplace, the separation was done with grease belts; diamonds have a stronger tendency to stick to grease than the other minerals in the ore.
Historically, diamonds were found only in alluvial deposits in Guntur and Krishna district of the Krishna River delta in Southern India. India led the world in diamond production from the time of their discovery in approximately the 9th century BC to the mid-18th century AD, but the commercial potential of these sources had been exhausted by the late 18th century, and at that time, India was eclipsed by Brazil where the first non-Indian diamonds were found in 1725. Currently, one of the most prominent Indian mines is located at Panna.
Diamond extraction from primary deposits started in the 1870s after the discovery of the Diamond Fields in South Africa. Production has increased over time and now an accumulated total of 4,500,000,000 carats have been mined since that date. Twenty percent of that amount has been mined in the last five years, and during the last 10 years, nine new mines have started production; four more are waiting to be opened soon. Most of these mines are located in Canada, Zimbabwe, Angola and one in Russia.
In the U.S., diamonds have been found in Arkansas, Colorado, New Mexico, Wyoming, and Montana. In 2004, the discovery of a microscopic diamond in the U.S. led to the January 2008 bulk-sampling of kimberlite pipes in a remote part of Montana. The Crater of Diamonds State Park in Arkansas is open to the public and is the only mine in the world where members of the public can dig for diamonds.
Today, most commercially viable diamond deposits are in Russia — mostly in Sakha Republic, for example Mir pipe and Udachnaya pipe, Botswana, Australia and the Democratic Republic of the Congo. In 2005, Russia produced almost one-fifth of the global diamond output, according to the British Geological Survey. Australia boasts the richest diamantiferous pipe, with production from the Argyle diamond mine reaching peak levels of 42 metric tons per year in the 1990s. There are also commercial deposits being actively mined in the Northwest Territories of Canada and Brazil.
Theft
On February 18, 2013, eight masked gunmen in two cars with police markings stole approximately $50 million worth of diamonds from a Swiss-bound Fokker 100 operated by Helvetic Airways on the apron at Brussels Airport, Belgium, just before 20:00 Central European Time. The heist was accomplished without a shot being fired. The whole robbery took about 20 minutes. The robbery did not appear to disturb any of the passengers, who did not know that anything had happened until they were told to disembark because the flight had been cancelled. In May 2013, 31 people were arrested in connection with the theft, and some of the diamonds were recovered. Charges were brought against 19 of those — 16 men and 3 women. In May 2018, 18 of those tried in connection to the heist were acquitted. The case against Bertoldi, the suspected mastermind, was yet to be heard, pending the outcome of his appeal over his kidnapping conviction. In June 2019, the correctional tribunal of Brussels sentenced Bertoldi to five years of imprisonment and a fine for being a co-conspirator in the heist, for being part of a criminal organization and for money laundering.
According to the article “The Most Expensive Diamond Jewelry in the World” in Love Happens magazine, here are some examples — with the exclusion of the aforementioned Hope Diamond.
Pink Star
The Pink Star diamond ring was sold at Sotheby’s auction for $71.2 million. This diamond jewelry became the costliest jewel ever sold in a sale. The Pink Star — also referred to as Steinmetz Pink — has this flawless pink diamond that weighs 59.6 carats. It originated in Africa in 1999 and had around 132.5 carats before it was cut.
Oppenheimer Blue
The Oppenheimer Blue diamond was the most expensive gem ever sold in an auction before the Pink Star grabbed the title. It was sold at Christie’s auction for $57.5 million. It weighs around 14.62 carats. It first belonged to Sir Philip Oppenheimer, who was a member of the Oppenheimer family who managed the De Beers Mining Company and the Diamond Trading Company from 1929 to 2012.
L'Incomparable
This classic diamond necklace has the largest internally flawless diamond in the world and is the most expensive chain all over the globe. The L’Incomparable diamond necklace consists of a 407.48-carat diamond and 230 carats of smaller diamonds. It costs around $55 million.
Blue Moon of Josephine
The Blue Moon of Josephine is a 12.03-carat blue diamond ring that originated in the Cullinan mine in South Africa in 2014. It was bought by Joseph Lau, a Hong Kong billionaire and collector, at an auction for $48.4 million. It got its name after Joseph’s daughter, Josephine.
Graff Pink
The Graff Pink is a pink diamond ring that weighs about 24.78 carats and was initially owned by Harry Winston. The jeweler Laurence Graff bought it at auction for $46.2 million.
Perfect Pink
The Perfect Pink diamond ring is priced at $23.2 million. It has a perfect cut, color and clarity, hence its name. It is a 14.23-carat intense pink diamond that is very beautiful and enchanting.
Heart of the Ocean
Harry Winston fashioned the Heart of the Ocean diamond necklace, which was once worn in the Oscars. It is a 15-carat blue diamond and priced at $20 million. The Heart of the Ocean necklace is one of the most expensive necklaces in the world.
So glad you are enjoying it! 😀
Amazing. Interesting. Informative. Another good read. Thanks.