Diamond is a crystallised form of the element carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewellery. Diamonds have superlative physical qualities and make excellent abrasives because they can only be scratched by other diamonds, which also means they hold a polish extremely well and retain lustre. Approximately 130 million carats are mined each year with a total value of nearly USD $9 billion.
The name “Diamond” derives from the ancient Greek word “adamas” which means “invincible”. They have been treasured since their use as religious icons in India at least 2,500 years ago and their use as drill bits and engraving tools dates to early human history. Popularity of diamonds has risen since the 1800s because of increased supply, improved cutting and polishing techniques and innovative advertising campaigns. Synthetic diamonds are produced each year at nearly four times the rate of natural diamonds, the vast majority of “fake” diamonds produced are small imperfect diamonds suitable only for industrial-grade only though.
Nearly half of all diamonds originate from Africa, although significant deposits have been discovered in Canada, India, Australia, Russia and Brazil. They are generally mined from volcanic pipes deep in the Earth where high pressure and temperatures enable the formation of the diamond crystals.
Diamonds are formed by the prolonged exposure of carbon bearing materials to extremely high pressure and temperatures. The formation of diamonds is possible because there are regions deep within the Earth that is thermodynamically favourable.
Under the Earths continental crust, diamonds form starting at depths of about 90 miles, where temperatures reach 1200 degrees Celsius. Long periods of exposure to these high pressures and temperatures allow diamond crystals to grow larger.
Diamonds can also form in other natural events. Very small diamonds have been found in impact craters where meteors strike the Earth and create shock zones of high pressure and temperature where diamond formation can occur. Microdiamonds are now used as one indicator of ancient meteorite impact sites.
Diamond-bearing rock is forced to the surface through volcanic eruptions. Below volcanic craters are formations known as volcanic pipes, which contain material that was pushed toward the surface, but did not erupt before the volcanic activity ceased. Diamond-bearing volcanic pipes are most commonly found in the oldest regions of the Earths continental crust
The magma in volcanic pipes is usually one of two types, which cool into igneous rock known as kimberlite or lamproite. The magma itself does not contain diamond, it merely acts as an elevator carrying deep-formed diamond bearing rocks and material towards the surface. Certain indicator minerals typically occur within kimberlites and are used by prospectors when searching for diamond deposits.
Once diamonds have been forced to the surface in a volcanic pipe, over time they may erode out and be distributed over a very large area. A diamond deposit in a volcanic pipe is known as a primary deposit. Secondary deposits include areas where diamonds, eroded out, accumulate because of water or weather action. These include alluvial deposits and deposits along existing and ancient shorelines, where loose diamonds tend to accumulate because of their size and density. Diamonds have also been found in deposits left by glaciers, however, in contrast to alluvial deposits, glacial deposits are not known to be of significant concentration and are therefore not viable commercial sources of diamond.
History of Diamond
Diamonds are thought to have been first mined in India, where significant alluvial deposits could then be found. The earliest written reference can be found in the Sanskrit text Arthasastra, which was completed around 296 BCE. Diamonds quickly became used to decorate religious icons, and were believed to bring good fortune to those who carried them. Ownership was restricted among various castes by colour, with only kings being allowed to own all colours of diamond.
In February 2005, a team of archaeologists discovered ceremonial burial axes originating from China’s Liangzhu and Sanxingcun cultures (4000-2500 BCE) which scientists believe were polished using diamond powder. Although there are diamond deposits now known to exist close to the burial sites, no direct evidence of mining has been found.
Diamonds were traded to both the east and west of India and were recognized by various cultures for their gemmological or industrial uses. In his work Naturalis Historia, the Roman writer Pliny the Elder noted diamond’s ornamental uses, as well as its usefulness to engravers because of its hardness. In China, diamonds seem to have been used primarily for engraving jade and drilling holes in beads. Archaeological evidence from Yemen suggests that diamonds were used as drill tips as early as the 4th century BCE. In Europe, however, diamonds disappeared for almost 1,000 years following the rise of Christianity because of two effects: early Christians rejected diamonds because of their earlier use in amulets, and Arabic traders restricted the flow of trade between Europe and India.
Until the late Middle Ages, diamonds were most prized in their natural octahedral state, perhaps with the crystal surfaces polished to increase lustre and remove foreign material. Around 1300, the flow of diamonds into Europe increased via Venice’s trade network, with most flowing through the low country ports of Bruges, Antwerp, and Amsterdam. During this time, the taboo against cutting diamonds into gem shapes, which was established over 1,000 years earlier in the traditions of India, ended allowing the development of diamond cutting technology to begin in earnest. By 1375, a guild of diamond polishers had been established at Nuremberg. Over the following centuries, various diamond cuts were introduced which increasingly demonstrated the fire and brilliance that makes diamonds treasured today: the table cut, the briolette (around 1476), the rose cut (mid-16th century), and by the mid-17th century, the Mazarin, the first brilliant cut diamond design.
In 1919, Marcel Tolkowsky developed an ideal round brilliant cut design that has set the standard for comparison of modern gems; however, diamond cuts have continued to be refined.
The rise in popularity of diamonds as gems seems to have paralleled increasing availability through European history. In the 13th century, King Louis IX of France established a law that only the king could own diamonds. However, within a century diamonds were popular gems among the moneyed aristocratic and merchant classes, and by at latest 1477 had begun to be used in wedding rings. Popularity continued to rise as new cuts were developed that enhanced the diamond’s aesthetic appeal, and has largely continued unabated to this day; diamonds have proven popular with all classes in society as their cost has become within reach. A number of large diamonds have become historically significant objects, as their inclusion in various sets of crown jewels and the purchase, sale, and sometimes theft of notable diamonds, have sometimes become politicized.
The Diamond Industry
A large trade in gem-grade diamonds exists. Unlike precious metals, diamonds do not trade as a commodity and there is a substantial mark-up in the sale of diamonds. There is not a very active market for resale of diamonds. One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to a few locations (most importantly New York, Antwerp, London, Tel Aviv, Amsterdam and Surat), and a single company “De Beers” controls a significant proportion of the trade in diamonds. They are based in Johannesburg, South Africa and London, England.
The production and distribution of diamonds is largely consolidated in the hands of a few key players, and concentrated in traditional diamond trading centers (the most important being Antwerp). The De Beers company holds a clearly dominant position in the industry, and has done so since soon after its founding in 1888. De Beers owns or controls a significant portion of the world’s rough diamond production facilities (mines) and distribution channels for gem-quality diamonds. The company and its subsidiaries own mines that produce some 40 percent of annual world diamond production. At one time it was thought over 80 percent of the world’s rough diamonds passed through the Diamond Trading Company (DTC, a subsidiary of De Beers) in London, but presently the figure is estimated at less than 50 percent. De Beers used its monopoly position to establish strict price controls, and market diamonds directly to consumers in world markets.
The De Beers diamond advertising campaign is acknowledged as one of the most successful and innovative ones in history. N.W. Ayer & Son, the advertising firm retained by De Beers in the mid-20th century, succeeded in reviving the American diamond market and opened up new markets, even in countries where no diamond tradition had existed before. N.W. Ayer’s multifaceted marketing campaign included product placement, advertising the diamond itself rather than the De Beers brand, and building associations with celebrities and royalty. This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the now-familiar slogan “a diamond is forever”.
Because of their extraordinary physical properties, diamonds have been used symbolically since near the time of their first discovery. Perhaps the earliest symbolic use of diamonds was as the eyes of Hindu devotional statues. The diamonds themselves were thought to be endowments from the gods and were therefore cherished. The point at which diamonds began to be associated with divinity is not known, but early texts indicate that it was recognized in India since at least 400 BCE. It is said the Greeks believed diamonds were tears of the gods; the Romans believed they were splinters of fallen stars. Many long dead cultures have sought to explain diamond’s superlative properties through divine or mystical affiliations.
In Western culture, diamonds are the traditional emblem of fearlessness and virtue, but have also often associated with power, wealth, crime and misfortune. Today, diamonds are used to symbolize eternity and love, being often seen adorning engagement rings and sometimes wedding rings as well. The popularity of this modern tradition can be traced directly to the marketing campaigns of De Beers, starting in 1938. Prior to the De Beers marketing campaign, engagement rings had no one particular stone associated with them. The first diamond engagement ring can be traced to the marriage of Maximilian I (then Archduke of Austria) to Mary of Burgundy in 1477. Other early examples of betrothal jewels incorporating diamonds include the Bridal Crown of Blanche (ca. 1370–80) and the Heftlein brooch of Vienna (ca. 1430–40), a pictorial piece depicting a wedding couple. Inaccessibility of diamonds to the vast majority of the population limited the popularity of diamonds as betrothal jewels during this period.
The diamond is the birthstone for people born in the month of April, and is also used as the symbol of a sixty-year anniversary, such as a Diamond Jubilee (see hierarchy of precious substances).