Diamond is one of the best-known and most sought-after gemstones. Diamonds have been known to humankind and used as decorative items since ancient times; some of the earliest references can be traced to India.
Diamond's hardness and high dispersion of light – giving the diamond its characteristic "fire" – make it useful for industrial applications and desirable as jewellery. Diamonds are such a highly traded commodity that multiple organisations have been created for grading and certifying them based on the four Cs, which are carat, cut, colour, and clarity. Other characteristics, such as shape and presence or lack of fluorescence, also affect the desirability and thus the value of a diamond used for jewellery.
Perhaps the most famous use of the diamond in jewellery is in engagement rings, which became popular in the early to mid 1900s due to an advertising campaign by the De Beers company, though diamond rings have been used to symbolise engagements since at least the 15th century. The diamond's high value has also been the driving force behind dictators and revolutionary entities, especially in Africa, using slave and child labor to mine blood diamonds to fund conflicts.
History
The Hope Diamond. Its deep blue coloration is caused by trace amounts of boron in the diamond
Early references to diamonds in India come from Sanskrit texts.
Diamonds eventually spread throughout the world, even though India had remained the only major source of the gemstone until the discovery of diamonds in Brazil.
Diamonds were traded to both the east and west of India and were recognised by various cultures for their gemological 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. It is however highly doubtful that Pliny actually meant diamonds and it is assumed that in fact several different minerals such as corundum, spinel, or even a mixture with magnetite were all referred to by the word "adamas".
Today, 92% of the world's diamonds are cut and polished in India, mostly in the city of Surat.. Antwerp's association with diamonds began in the late 15th century when a new technique to polish and shape the gems evolved in this city. The diamond cutters of Antwerp are world renowned for their skill. More than 12,000 expert cutters and polishers are at work in the Diamond Quarter, at 380 workshops, serving 1,500 firms and 3,500 brokers and merchants.
In the 21st century, the technology to produce perfect diamonds synthetically was developed. Diamonds produced by the latest technologies are visually identical to mined, naturally-occurring diamonds. It is too early to assess the effect of future wide availability of gem-quality synthetic diamonds on the diamond market, although the traditional diamond industry has already taken steps to try to create a distinction between diamonds dug from the ground and diamonds made in a factory, in part by downplaying the fact that diamonds from both sources are actually identical.
Gemological characteristics
The most familiar usage of diamonds today is as gemstones used for adornment - a usage which dates back into antiquity. The dispersion of white light into spectral colours, is the primary gemological characteristic of gem diamonds. In the twentieth century, gemologists have developed methods of grading diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics known informally as the four Cs are now commonly used as the basic descriptors of diamonds: carat, cut, color, and clarity.
Most gem diamonds are traded on the wholesale market based on single values for each of the four Cs; for example knowing that a diamond is rated as 1.5 carats (300 mg), VS2 clarity, F colour, excellent cut round brilliant, is enough to reasonably establish an expected price range. More detailed information from within each characteristic is used to determine actual market value for individual stones. Consumers who purchase individual diamonds are often advised to use the four Cs to pick the diamond that is "right" for them.
Other characteristics also influence the value and appearance of a gem diamond. These include physical characteristics such as the presence of fluorescence as well as the diamond's source and which gemological institute evaluated the diamond. Cleanliness also dramatically affects a diamond's beauty.
There are three major non-profit gemological associations which grade and provide reports or certificates ("certs") on diamonds; while carat weight and cut angles are mathematically defined, the clarity and colour are judged by the trained human eye and are therefore open to slight variance in interpretation. These associations are listed below.
Gemological Institute of America (GIA) was the first laboratory in America to issue modern diamond reports, and is held in high regard amongst gemologists for its consistent, conservative grading.
American Gem Society (AGS) is not as widely recognised nor as old as the GIA but garners a high reputation. The AGS employs a number system for grading cut quality, colour grade, and clarity. The highest grade being '0', and the lowest being '10'.
Diamond High Council (HRD) Official certification laboratory of the Belgian diamond industry, located in Antwerp.
Within the last two decades, a number of for-profit gemological grading laboratories have also been established, many of them also based in Antwerp or New York. These entities serve to provide similar services as the non-profit associations above, but in a less expensive and more timely fashion. They produce certificates that are similar to those of the GIA.