Diamonds On your next trip to the local shopping mall, stop by one of the jewellery stores. Notice the diamond jewellery that takes up the majority of the showcase, and the number of people hovering over the counters trying to pick out a diamond for their loved one. There will surely be a salesperson explaining the "4 Cs" -- cut, clarity, carat and colour . Other unique qualities of the diamond include its transparency, lustre and dispersion of light. A diamond that is created from 100-percent carbon will be completely transparent. Diamonds often contain other elements that can affect the colour. Although we often think of diamonds as being clear, there are also blue, red, black, pale green, pink and violet diamonds. These coloured diamonds are the truly rare ones. Diamonds are just carbon in its most concentrated form. That's it -- carbon, the element that makes up 18 percent of the weight of your body. In many countries, including the United States and Japan, there is no other gemstone as cherished as the diamond, but in truth, diamonds are no more rare than many other precious gems. They continue to demand higher market prices because the majority of the diamond market is controlled by a single entity. Diamonds form about 100 miles (161 km) below the Earth's surface, in the molten rock of the Earth's mantle, which provides the right amounts of pressure and heat to transform carbon into a diamond. Most diamonds that we see today were formed millions (if not billions) of years ago. Powerful magma eruptions brought the diamonds to the surface. Diamonds are found as rough stones and must be processed to create a sparkling gem that is ready for purchase. Diamonds were not always so popular with the American public, and they were not always so pricey. The only reason why we pay so much more for diamonds today than for other precious gems is because the diamond market is controlled almost entirely by a single diamond cartel, called De Beers Consolidated Mines, Ltd., which is based in South Africa. The secret to De Beers' success is a marketing campaign that convinces women that they should receive a diamond ring from their fiancee and convinces young men to pay "two-months salary" for that ring to show how much their love is worth. Prior to the 1930s, diamond rings were rarely given as engagement rings. This idea of connecting diamonds to romance was captured in a brilliant ad campaign begun in the 1940s, causing demand for diamonds to increase. Surely you've heard the De Beers advertisement telling you that "A Diamond is Forever."