How Are Diamonds Made?
Diamonds form naturally deep beneath the Earth's surface, but they can also be made in a laboratory by diamond manufacturers. Read on to learn about the interesting facts about this highly sought after gemstone.
You may have asked yourself more than once, "What makes diamonds so special and rare? Why do people make such a big fuss about a little rock?" Diamonds are in a class all by themselves for good reason. The reality is no diamond is born looking pretty. A lot of work goes into the making of a diamond as we know it. Diamond deposits dwell deep below the earth and are brought up through volcanic eruptions. They are like every other crop waiting for the harvest moon. But unlike other crops, diamonds wait millions and even billions of years before they reach maturity. There's a lot about diamonds that most people don't readily know. Here's a quick rundown of the most basic yet astounding facts you need to know about diamonds:
• Diamonds are nothing more than crystallized carbon atoms, except they're the priciest carbon atoms you'll ever find. It's the specific arrangement of atoms that determines the end result. Take, for instance, the graphite commonly associated with pencils. That, too, is nothing but carbon but due to its unique atomic structure, it is the complete opposite of diamonds, soft and gray black, versus very hard and colorless.
• To get to its final stage, diamonds are more or less baked for over a billion years approximately 100 miles beneath the earth's surface. They are exposed to extreme temperatures and high pressure before they make their way above the surface.
• You pay a pretty price for rarity: 250 tons, or 500,000 pounds, of earth must be mined to uncover just one carat of rough diamonds. Unfortunately, rough diamonds lose an average 50%-60% of their original weight once they are cut and polished. Smaller diamonds are more common than larger ones, which is why a two-carat diamond is more than twice the price of two one-carat diamonds. Of all the rough diamonds found, only about 20% of make the cut as gemstones.
• Only one in a million diamonds are gem quality one-carat stones; one in five million are gem quality two-carat stones; and one in 15 million are gem quality three-caraters. You may have a better chance of striking gold (or diamonds) by playing the lottery!
• The melting point of diamonds is 6,420 degrees Fahrenheit and the boiling point is 8,720 degrees Fahrenheit.
• The largest diamond ever mined in the world was the Cullinan. It was discovered in South Africa in 1905 and checked in at a jaw dropping 3,106.75 carats.
• The largest diamond in the universe is the 10 billion trillion trillioncarater named Lucky, or BPM 37093, which is a "white dwarf" star that has burned out and died, leaving its hot core to crystallize. Like a typical diamond, it is composed of carbon. It lies approximately 50 light years from our planet in the constellation Centaurus. Our sun, too, will one day die and crystallize into a monstrous diamond just like Lucky, but not for another five to seven billion years.
Natural diamonds are formed from pure carbon at a depth of around 80-120 miles below the Earth's surface. The process of diamond formation occurs over millions (or even billions) of years within the molten rock of the Earth's mantle, where the right amounts of pressure and heat can be found to transform carbon into diamond. The diamonds are then carried through flows of molten lava to the Earth's surface where it is mined and turned into the precious stones we used to make jewellery.
Fancy Colored Diamonds
Colorless diamonds are rare enough, but naturally occurring fancy colored diamonds are rarer still, which explains why they often command the highest prices at auction. Diamonds can come in all sorts of colors, from vivid blues to fiery oranges, but how do they get these spectacular colors in the first place?
Fancy colored diamonds ('fancy' denotes that the diamond acquired its color naturally, rather than being artificially treated) occur in nature for several reasons. A colorless or "white" diamond is made of 100% carbon. When another element gets into the carbon chain, it can add a color, for instance, nitrogen causes yellow, brown and pink hues, while boron produces blue or blue-grey. Hydrogen can cause diamonds to become red, violet, blue or green.
Another way for the stones to acquire color is via unusually intense pressure or heat during the compression stage that gives birth to diamonds: this can lead to red, pink or purple diamonds. Naturally occurring radiation can also affect the color, making diamonds blue or green, mines in certain parts of the world have a greater chance of unearthing these.
One particularly interesting variety is carbonado, the "black diamond". These diamonds have a different crystalline structure to regular diamonds that makes them absorb light rather than reflecting it. They have traditionally been associated with bad luck and sold at lower prices than regular diamonds, although recently their distinctiveness has seen them gain in popularity.
What makes carbonado fascinating is that scientists can't agree on how it is formed: some say it's made when meteorites strike the Earth, others by direct conversion of carbon in the planet's interior, while still others say it's formed inside dying stars, and is blasted to Earth via a supernova. To date, black diamonds have only been found in Central Africa and Brazil.
The presence of a color might seem like it makes the diamond technically less 'pure', but the rarity and sheer beauty of these stones makes them highly sought after. To illustrate just how rare they are, a mine producing 35 million carats (seven metric tonnes) a year would consider itself lucky if it found four or five of the rarest colored diamonds in that time!
There are two ways of making synthetic diamonds in a laboratory, both of which are used by diamond manufacturers. The first synthetic method is known as 'high pressure, high temperature', or HPHT for short. This method is the closest thing to the diamond production process that occurs naturally within the Earth, and involves subjecting graphite (which is made from pure carbon) to intense heat and pressure.
Tiny pieces of metal in the HPHT machine are used to squeeze down the graphite as it is zapped with an intense pulse of electricity. This process takes just a few days and results in a gem quality diamond. Unfortunately, this type of synthetic diamond is not as pure as a natural diamond, because part of the metallic solution used to form the diamond can become mixed in with the graphite.
The second diamond producing method is called chemical vapour deposition. This method produces diamonds even more flawless than those found in nature. Chemical vapour deposition involves placing a piece of diamond into a depressurising chamber, where it is treated with a natural gas under a microwave beam. When the gas heats to around 2,000 degrees, carbon items rain down onto the diamond and stick to it. Using this process, manufacturers can grow a perfect sheet of diamond overnight.
While prospectors have been looking for gems in Canada since at least the 1960s, diamond rich areas were not discovered in the country until 1991, when the first economic diamond deposit was discovered in the Lac de Gras area of the Northern Territories. Since then, the country has quickly become one of the world leaders in diamond production.
Canadian diamonds are prized not only for the high quality of the diamonds themselves, but also because of the nation's highly ethical approach to the industry. All diamonds mined in Canada are guaranteed to be conflict-free, and indeed Canada has long been one of the most vocal supporters of the Kimberley Process Certification Scheme, designed to stem the diamond trade's contribution to violence and war.
Diavik Mine, located in a remote part of Canada's Northwest Territories, is one of the world's most productive open-pit diamond mines. It produces around eight million carats per year, that's 1.6 metric tonnes of diamonds, and represents about six per cent of the world's supply. The nearby Snap Lake Mine is owned by diamond mining giant De Beers, the company's first mine outside of Africa, and produces around 1.4 million carats annually. Other major diamond mines in Canada include Ekati Mine, Victor Mine and Jericho Mine.
All diamonds mined and cut in Canada's Northwest Territories are laser-inscribed with identification numbers so that buyers and retailers can be assured that the stones have been mined and traded ethically. Canada also has stringent rules regarding its mines' effects on local habitats and ecosystems; its diamonds are mined to the highest environmental standards in the world. A large proportion of employees in the mines are of Canadian Aboriginal origin, so the industry is also helping to support and bring prosperity to the region's indigenous people.