Diamonds burn brightly as symbols of love. For centuries, they have conquered hearts, launched romances, marked anniversaries. Kings and queens covet them. Movie stars flash them. Some of the planet's hottest and coldest spots produce them. In story and song, the desire for diamonds is as enduring as diamonds themselves. Sifting mountains of rock, in the harshest of climates, produces rough diamonds. A ton of diamond-bearing rock may yield half a carat. If it is earth's ability to squeeze carbon into the hardest substance known, it is the hand of man that coaxes out its luminous personality.

Slip a diamond on your finger and you wear a piece of geological history 70 million years old. Though diamonds are cut to rigorous standards, nature endows each with its own identity. Tiny quirks, most invisible to the naked eye, exist in the form of specks, bubbles and feather-like lines. Among the millions of carats mined each year, truly flawless diamonds number in the hundreds. These rarest of beauties are the costliest.

What many people don’t know about diamonds is that they were formed under immense heat and pressure hundreds of miles below sea level. After 100 million years of formation, volcanic explosions forced them upward, exposing their natural beauty to the world. After the magma cooled, it solidified into blue ground, or kimberlite, where the precious rough is still found today. Rated 10 on the Mohs scale of hardness, diamonds are the hardest substances on earth, but their appeal goes far beyond durability.

Adding to the mystery and aura of what make diamonds so sought-after, approximately 250 tons of ore must be mined and processed in order to produce a single, one-carat, polished, gem-quality diamond.

It was over 4,000 years ago that the first diamonds were mined in India. Modern mining as we know it today began in South Africa in the late 19th century. Today, the top seven diamond-producing countries, accounting for 80 percent of the world’s rough diamond supply, are Botswana, Russia, South Africa, Angola, Namibia, Australia and Zaire.