AN EXCEPTIONAL STONE

What is a Diamond?

Diamond is pure carbon—so pure it has become the world’s most coveted gem and an indispensable industrial material. When analyzed from a standpoint of chemical composition, diamond is found to be made of the same ubiquitous, basic elements as coal or graphite—but with one big difference. Coal and graphite are exceedingly soft and diamond is exceedingly hard.

Why the difference? It’s got to do with atoms. Diamond has the most tightly packed, concentrated, uniform arrangement of atoms of any type of carbon. Here’s how its chemistry works: All carbon atoms have 6 electrons, four of which are available to bond with neighboring carbon atoms. This is called forming a valence. In every kind of carbon, except diamond, only three of the four electrons bond with their neighbors. This makes the atom structure kind of slippery and easily parted. Hence graphite and coal are very soft (or, if you prefer, weak). Diamond, on the other hand, uses all four valence electrons for chemical bonding. And that extra linkage throughout the carbon specimen allows it to crystallize into the hardest mineral known to man. In fact, the name diamond pays tribute to this hardness. It’s taken from the ancient Greek word adamas, which means unbreakable.

How is Diamond Formed?

In Superman III, the Man of Steel takes a lump of coal, squeezes it hard, and, voila, it becomes a diamond to give his girl friend Lois Lane. This feat of strength tells you as much about the creation of diamond as it does the might of Superman. Mother Nature, who is a superwoman in her own right, had to go at least 100 miles under the earth’s surface to duplicate the conditions in Superman’s fist. You see, diamond could not be made at or near the earth’s surface. There just isn’t the kind of near-melting-point heat and crushing pressure needed to make something as pure and hard as diamond. Creation could only occur down in the earth’s mantle—that nearly 3,000 kilometer-thick middle zone between this planet’s thin crust and its thick core. What’s more, diamond creation may have started when things were much hotter on planet earth—possibly soon after the earth took its present geologic form 4.5 billion years ago, when the earth’s mantle to the earth’s crust was made. How did the diamond make the long trip to places where it could be picked up as a natural antiquity? It also makes every diamond a supernormal mineral with lots of superlative qualities. All of this brings us to one of the most fascinating parts of the diamond’s story: its ride from the ground. What was its mode of conveyance? Volcanoes. Diamonds were shot like rockets from deep below the earth’s surface. And it is this means of transport which explains why they were created so strong. It takes toughness to survive a volcano ride.

They Came from Inner Space: The Diamond’s Trip to the Earth’s Surface Diamond wasn’t made peerlessly hard just so it could glitter with incomparable brilliance and fire. Nor was it made tough to stand up to the rigors of daily wear and tear. It was made hard for traumatic travel to the earth’s surface. As pure, intensely compacted carbon which crystallized in the earth’s upper mantle, diamond was first carried ground-ward in surging, wild rivers of molten rock called magma. If you’ve ever seen pictures of active volcanoes, you’ll see ingot-red streams of magma pouring from them like sauce boiling over from a pot. Diamond was made to survive conditions that would have melted meeker minerals. But the river ride up through the mantle was just stage one of the diamond’s journey to the earth’s surface. True, that was the longest part of the journey, taking diamond to just a couple of kilometers below the ground.

Then came the grand finale. After riding the volcanic rapids of magma for possibly hundreds of miles, diamond was carried to within striking distance of the miner’s pick and shovel in a final ultra-violent eruption of debris and gas. This last volcano blast left the lion’s share of diamonds embedded in volcanic rock known as kimberlite and lamproite. (Kimberlite is named after Kimberly, South Africa, where diamonds were discovered in 1868.) These rock formations (also called “pipes”) resemble funnels with narrow bottoms and wide cone-shaped tops. These funnel-like passageways to the earth’s surface supply the vast majority of the world’s diamonds. However, only one in fifty kimberlite pipes contain diamonds. And of these, most contain so few of them they cannot be mined profitably. Although diamonds can be said to come from deep in inner space, the fact that they consist of extra-terrestrial matter means they may predate the earth. In this way, it can also be said that diamonds—or, at least, the stuff from which they’re made—came from outer space. Most other carbon forms were derived from later living matter that got recycled back into the earth’s mantle. So we’re talking one very tough, very ancient mineral.

Did You Know?

• in ancient times, the diamond was considered a symbol of power
• in India, diamonds were set in the eyes of Hindu statues
• monarchs decorated their swords and scabbards with diamonds
• diamonds were also sewn into clothing as symbols of status
• ancient Greeks thought diamonds were the tears of gods
• Romans believed that diamonds were splinters from falling stars
• diamonds were said to protect from harm
• diamonds were also thought to bring luck and success
• diamonds were considered the ultimate symbol of love as far back as the fifteenth century
• Cupid's arrow was said to be tipped with diamonds