Diamonds: The whole story

A symbol of innocence, justice, faith, and strength, the diamond was believed to make its wearers courageous and victorious over their enemies. When set in gold and worn on the left side, it held the power to drive away nightmares and soothe savage beasts. Diamonds were even thought to be so powerful that they could stop lechery.

Diamonds were believed to sweat in the presence of poison and were often worn to ward it off, yet believed to be deadly itself if swallowed. Some people believed that the finest diamonds could reproduce themselves. Certain exceptional stones, when moistened with morning dew and left in the dark, would supposedly produce offspring, though given the ongoing development of new diamond mines, this technique probably met with scant success.

The Hindus believed that this brilliant gem was created when bolts of lightning struck rocks. To be effective as a talisman, the gem would have to be given as a token of love or friendship. If bought and sold, it would lose its powers. April's birthstone is said to be at its most potent when set in steel.

The Facts
It is the hardest natural substance--four times harder then the next hardest material, corundum (sapphire and ruby). As a gemstone, diamond's single flaw (perfect cleavage) is far outdistanced by the sum of its positive qualities. It has a broad color range, high refraction, high dispersion or fire, very low reactivity to chemicals, rarity, and of course, extreme hardness and durability.

This incredible gem began life about 3 billion years ago (give or take a million), deep beneath the Earth's surface, when enormous heat and pressure squeezed together carbon C atoms into the most atomically dense substance known -- a crystal that, because of its density, is not just transparent, but is a playground for light.

How much pressure does it take to make a diamond? Imagine the Eiffel Tower turned upside down, with all its weight resting on a plate 5 inches square. This is definitely not something you can make at home.

The diamonds that make it to the surface were forced up volcanically, to form kimberlite pipes near the surface--like a gigantic carrot encrusted with diamonds. Once found, it takes several years to dig up the whole pipe and extract the diamonds, which can be a whole range of sizes from sandpaper grade to monsters the size of a human fist.

Diamonds are mined in many parts of the world, but 80% of the stones on the market today come from Angola, Australia, Botswana, Namibia, South Africa, Russia and Zaire. All of these sources might appear to indicate great availability, but this is not the case. More than 250 tons of ore need to be blasted, crushed and processed to yield just one carat of rough diamond. If that weren't enough, most of the rough extracted from the ground is not suitable for gems; only about 20% of all rough diamonds are suitable for gems cutting.

They could hardly be called beautiful in the rough--they look a bit like glass that has been washed up on a beach. They are ready to be cut and polished -- not an easy task with the Earth's hardest substance.

Hard as it is, it is not invincible--fortunately for us. Because it is a crystalline formation, diamond has four directions of cleavage. If it receives a sharp accurate blow in one of these directions it will cleave, or split. If it weren't for this tendency, humans might never have started cutting diamonds into gemstones.

The first place it goes is to a cleaver or sawyer--depending on the cleavage of the stone. Their job is to cleave or cut the diamond into two pieces to bring out the best angle, establishing what the final cut will be.

Sawing is a lengthy process, whereas cleaving is finished the instant after the diamond is lit by a sharp blow from a blade and hammer. However, some stones have too many stress points and might split into fragments if cleaved, so those go to the sawyer, who is slow, meticulous and safe--if a little more expensive.

After the stone has been cleaved or sawed, it goes through a series of cutters who each have their own specialty. The blocker cuts out the rough shape of the diamond, and the brilliandeers, divided into top maker and bottom maker, cut the table and facets above the girdle and cut the pavilion respectively. At the end of the cutter line is the girdler, who cuts the girdle and the facets around it. In many cases nowadays, these processes can be performed by incredibly precise computerized machinery, though the top quality stuff is still done by humans.

Completing the process is the longest step of all: polishing. Because of their extreme hardness, diamonds can be polished only by other diamonds, so fine diamond abrasives are used to create the stone's many angled planes, or facets. Each facet must be in perfect geometric proportion to every other in order to provide maximum reflection.

After this, the diamond is ready to be set. The journey finishes when it finally finds a home with someone who will wear it for a lifetime.