For all the beauty and complexity of a well-cut diamond, they are the simplest of gemstones in the chemical sense: pure carbon, the same as the graphite in a pencil.

They are formed under intense heat and pressure deep within the earth, and are forced to the surface by geological events.

Diamonds are harder than any other material on earth, earning them a 10 on the Mohs' scale of hardness. They can only be cut by other diamonds. Their hardness and other special qualities, such as how they refract light, allow them to be cut into the amazing gems we know today.

Gem-quality diamonds are mined around the world, but the largest producers are South Africa and its neighbors. Russia, Australia and Brazil are also major producers. Diamonds come from the mines in crystals, often with eight sides. As much as 60 percent of the original crystal is cut away to create a round brilliant diamond.