The Hardest Natural Substance!
With a hardness of ten on the Mohs Scale, diamond is the hardest natural substance. Diamonds are so hard that the only tools that can be used to cut a diamond must be made from another diamond.
USA: Top Diamond Consumer
The United States is the world's leading consumer of gemstones. In 2014 it consumed about $22.5 billion in unset gem-quality stones. That was about 35% of the world's gem diamond production.
India: The First Commercial Producer
Diamonds were discovered in India at least 2400 years ago and India was the first commercial producer of diamonds. The country dominated commercial diamond production until South American discoveries in the 1730's.
The Four "C's" of Diamond Value
The value of a diamond is based upon its carat weight, clarity, color and the quality of its cut.
Most diamonds are in a color range that runs from clear to yellow to brown. Colorless receive the highest grade and are generally of highest value.
A small number of natural diamonds fall outside of the typical white-yellow-brown color range. They are pink, blue, purple, red, orange or any color. Those of a pleasing hue are extremely valuable and are given the name "fancy" diamonds.
What Causes Colored Diamonds?
As in other gemstones, color variants in diamond can be caused by impurities, heat or irradiation. Nitrogen in the stone causes a yellow color. Irradiation can produce greens. Irradiation then heating can produce almost any color.
The Gem of Heat and Pressure
Diamonds are a high-temperature, high- pressure minerals. They do not form naturally at Earth's surface or at shallow depths. The conditions where they can form are in Earth's mantle about 100 miles below the surface.
Polymorph means "many forms". Diamond and graphite are polymorphs. They are both made up of carbon but have different properties. This results from their different crystal structures and different types of bonds between carbon atoms.
Synthetic Diamonds for Industry
People have been able to manufacture diamonds since the 1950's. At first the cost was very high. Now, over 100 tons of synthetic diamonds are produced every year. Most of these diamonds are used to make cutting tools and abrasives.
The Largest Diamond Deposit
The largest known diamond deposit is at Popigai Crater in Russia. There an asteroid impact provided enough heat and energy to convert carbon surface materials into diamond. The diamonds are of industrial quality.
Synthetic Diamonds for Jewelry
People have successfully made synthetic diamonds for use in fine jewelry. The stones are undistinguishable from natural diamonds, even when observed by experienced gemologists. They can be identified only by laboratory tests.
The Mine of Famous Diamonds
Most of the world's most famous diamonds have been found at the Cullinan Diamond mine in the Gauteng Province of South Africa. An example is the 507-carat "Cullinan Heritage", a Type IIA diamond of extreme quality and clarity.
Find it on Geology.com
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Canada: Future Production Leader?
Canada's first commercial gem-quality diamond mines delivered their first production in the late 1990's. In the short years since, Canadian diamond mines have become some of the world's leading producers.
You Can Mine Diamonds Here!
There is only one diamond mine in the world where anyone can be a miner.
That mine is at Crater of Diamonds State Park in Arkansas. For a few dollars you can mine for a day and keep anything you find.
Diamonds From Space!
Diamonds from space is a reality. They have been found in some meteorites and the impact of meteorites with Earth is thought to produce enough heat and pressure to transform carbon into diamonds.
Many uncut diamonds have a geometric shape. These natural diamond crystals commonly are in the form of an octahedron. This shape is similar to two four-sided pyramids connected at their base to form a geometric solid with eight faces.
Diamonds For Drilling
Drilling oil and gas wells down through thousands of feet of rock requires a tough drill bit. Small diamonds are embedded into the cutting surfaces of these bits. The extremely hard diamonds wear away the rock as the drill bit is turned in the hole.
Diamonds are used to make saw blades used to cut concrete, rock, brick and even gemstones. These are circular saws with a blade tipped with tiny particles of diamond. As the blade turns the diamonds saw through the concrete.
Diamonds form at high pressure and that makes them stable in such an environment. When scientists need to place small objects under ultra-high pressure they often press them between two pieces of diamond known as "diamond anvils".
One Element Gemstone
Diamonds have a simple composition. They are composed of carbon. Diamond is the only gemstone composed of just one element.
Trace amounts of other elements exist in diamonds as impurities. These can give diamond a slight color.
Record Price for a Rough Diamond
The highest price ever paid for a rough diamond was was $35.3 million. Chow Tai Fook, Hong Kong's largest jewelry company, purchased the 507-carat "Cullinan Heritage" 2010. It was cut into 24 D-color, internally flawless diamonds.
USA: Almost No Diamond Production
Although the United States is the largest consumer of gem diamonds it has almost no production. The only mine is a state park where tourists can pay a fee to look for diamonds. The park yields just a few hundred carats per year.