What exactly is a diamond?
As vintage vixen Marilyn Monroe sang, diamonds are a girl's best friend. They've come to symbolize the height of affluence and affection. Though the baubles have been in vogue only since the 1950s, these minerals have existed deep inside the Earth for billions of years.
And while they aren't any rarer than rubies, emeralds or sapphires, diamonds' unique properties put them a cut above the rest.
The Chemistry of Diamonds
Diamond is the most concentrated form of pure carbon in the natural world and the strongest mineral on Earth, far exceeding other carbon allotropes such as graphite and fullerite. The secret to diamond's superior strength is found on the molecular level. Carbon atoms possess four valence electrons available for bonding. In diamond crystals, each of those four free electrons forms a covalent bond with a valence electron of a neighboring carbon atom. Since all of the free electrons are bonded uniformly, it creates a rigid tetrahedral lattice that gives the coveted mineral its prized properties.
The Real McCoy: Natural Diamonds
The organic process of diamond formation requires four key ingredients: carbon, pressure, heat and time. When it comes to heat and pressure, the specific conditions are at least 752 degrees Fahrenheit (400 degrees Celsius) and 434,113 pounds per square inch (30 kilobars). Prime diamond real estate is located about 100 miles (160 kilometers) underground in the Earth's mantle. There, diamonds have formed over billions of years from heated and pressurized carbon.
Hundreds of millions of years ago, eruptions of magma from the mantle propelled natural diamonds closer to the Earth's surface. The funnel-shaped areas carved out by the magma eruptions are called kimberlite pipes, named for the first formation discovered in Kimberley, South Africa. Gradually, the tops of the pipes eroded, exposing the diamonds below. Erosion can also carry diamonds from their original location into riverbeds and coastal lands. In its roughest form, diamond ore doesn't look like the shiny nuggets atop engagement rings. Diamonds must be sorted, cut and polished to bring out their luster.
Fake, But Flawless: Synthetic Diamonds
Like 18th-century alchemists striving to turn common elements into gold, geologists long sought out methods for creating synthetic diamonds. According to the American Museum of Natural History, Swedish and American researchers cracked the carbon code in the 1950s to convert graphite and molten iron into diamond.
The most authentic man-made diamonds today are manufactured by subjecting pure carbon to intense heat and pressure in a simulation of the organic process. To the naked eye, these synthetic diamonds are indistinguishable from natural ones -- and fetch a lower price to boot.
Bling Bling: The Value of Diamonds
Since the cartel De Beers controls a majority of the world's diamonds, the price tag seldom drops. However, as the world's most durable mineral, diamonds are in high demand even outside of the fashion accessory market. According to the Natural Museum of History, diamonds conduct heat five times faster than copper, can pass or block electrical currents and endure extreme temperatures and chemical exposure. The sharpened gems are employed as specialized drill bits, for instance, and synthetic diamonds have opened the possibility of applying them to microchips and semiconductors.
Whether produced in the Earth's mantle or a high-powered pressure cooker, diamonds are valued equally for their beauty and their practicality. Given the gems' potential applications, tomorrow's diamond spokesperson may be more along the lines of Bill Gates than Marilyn Monroe.
Beyond exquisite jewelry, diamonds have many industrial uses. Diamonds are the hardest natural substance known that resists scratching. They are used for their durability to cut through many solid materials, including other diamonds. The beauty of how light passes through and shines upon a diamond has made it the favorite choice for jewelry and most popular gem around the world.
Identification
Diamonds gemstones are very rare. They are composed of carbon atoms that form tight bonds with each other to make the extremely durable diamond. Diamonds naturally exist 100 miles into the Earth's mantle. Volcano eruptions would surface large chunks o f the xenoliths, or mantle rocks. Diamonds are mined from these rocks and their sediments.
Diamonds as Gems
Diamonds with superior clarity are chosen specifically for jewelry. The value of diamonds is based on their quality, beauty, color, cut and carats. Diamonds are highly sort after for their high sparkle against gold, platinum, silver and other precious metals. Diamonds move light like a prism. The high refractive index and the high dispersion of diamonds causes light to bend and spread, showing all the colors of the rainbow. Most of the diamonds mined are not used for jewelry. In fact, four of five diamonds are used for industrial operations. These diamonds are called bort diamonds.
Diamonds Used as Abrasives
Diamonds are used as slurries and as cutting tools. Diamond slurries are a paste made of water and a mixture containing small diamond pieces. These slurries are used to grind down the surface of solid rock and other materials and for polishing their surfaces. Diamond slurries are also used in lapping, where the slurry is sandwiched between two surfaces. These surfaces are then rubbed together, so that the slurry grinds down the surfaces.
Engraving
Diamonds are used to engrave stones of granite, quartz and other hard materials. These diamonds will not scratch or break against the other stones, so the work can be completed without worrying about replacing the engraving bit.
Other Uses
Diamonds are also used in x-ray machines and lasers, as windows over enclosed parts. Diamonds enhance sound when made into a very durable speaker dome. In addition to the high refractive index and high dispersion, diamonds also have the highest level of thermal conductivity. Because of this quality, diamonds are used as heat sinks, to prevent heat damage to delicate parts, as in electronic applications. Diamonds are also used to prevent friction between microbearings, and to provide more durability to its mechanism parts.
Diamonds and International Trade
Diamonds are traded all around the world. Many people rely on the diamond industry for their earnings, where jewelers, diamond buyers and diamond miners exchange diamonds for profit. Diamonds are also most notably associated with criminal activity. Many people go to great lengths to possess diamonds, even resorting through theft and other illegal activities.
Future Uses
Future uses for diamonds may extend into medicine for surgical tools, medical devices and for the replacement of joints. Diamonds may also be used in computer parts, communication equipment and for sound materials and devices.
