Everyday Science: Diamond Quiz

A diamond is carbon in its most concentrated form, the same element that makes up 18 percent of the weight of a human body.

Most diamonds were formed millions of years ago, far below Earth's surface, in the mantle's molten rock. In the mantle, about 100 miles below the surface, the right combination of temperature and pressure acts on carbon and transform it into diamonds. In order for a diamond to be created, carbon must be placed under at least 435,113 pounds per square inch (psi, or 30 kilobars) of pressure at a temperature of at least 752 degrees Fahrenheit (400 degrees Celsius).

When powerful magma eruptions bring diamonds that were formed in the Earth's mantle to the surface, kimberlite pipes are created. The magma eventually cools inside these pipes, leaving behind conical veins of blue kimberlite rock that contain diamonds. They're named after Kimberley, South Africa, the place where they were first found.

The diamond sits atop the Mohs Harness Scale with a ranking of 10, meaning it can scratch any mineral and can only be scratched by another diamond. Its hardness can be attributed to its molecular structure, a lattice in which each carbon atom shares electrons with four other carbon atoms, forming a tetrahedral unit and a very strong molecule.

Bruiting is the process that gives a diamond its shape by cutting it by hand. Cutters do this by using the only thing able to cut a diamond -- another diamond.

It might surprise you, but most diamonds never make it to the case of your local jewelry store because they are too flawed. Those that don't make the cut are used for industrial purposes, as drill bits and to cut other diamonds.

The color scale for transparent diamonds runs from D to Z.. Icy white is the most expensive transparent diamond and is at the start of the scale. A transparent diamond is one created from 100 percent carbon.

There are fewer than 200 people or companies authorized to buy rough diamonds from De Beers. These people are called sightholders, and they purchase the diamonds through the Central Selling Organization (CSO), a subsidiary of De Beers that markets about 70 to 80 percent of the world's diamonds.

Blood diamonds, also known as conflict diamonds, are named for the blood that is often shed before the diamonds are sold. Militia and terrorist organizations force men, women and children in Africa to locate these diamonds. When the diamonds are sold, the militia and terrorist groups use the funds to purchase weapons and prolong their reign of terror. The United Nations (UN), the Conflict Free Diamond Council and other groups are working toward better regulation so conflict diamonds don't make it to the market.

Discovered in 1905 in Transvaal, South Africa, the Cullinan is the largest diamond ever found, weighing a whopping 3106 carats. The diamond was presented to King Edward VII of England in 1907 and later cut into nine major stones.