MATERIAL WORLD Buying the Rock

Diamond. Diamant. Diamante. SAY IT loud so they hear what you’re saying, say it soft and it’s almost like praying. They are absolutely a girl’s best friend and really are forever. They are the subject of innumerable fantasies and uncountable legends. Shelves of books, scores of films, hundreds of television episodes tell their tale. They symbolize love and purity in nearly every culture acquainted with their hard brilliance, from ancient India to postmodern Dallas.

Everyone knows that diamonds are essentially subterranean coal, made from plants, made from water, made from light and air of a prehistoric age. Torn from die earth’s shimmering magma heart, they crystallized and rode gigantic rock pipes to the surface, blasting to ground level on lava streams. There they collected in deposits of incalculable value, waiting for men in southern Africa, Australia, and Siberia to fetch them from their favorite swaddling of kimberlite ore. Occasionally, they are even picked up loose on the ground, gathered in baskets, sieved from rivers in shallow pans. All this, just to finally land on a lucky woman’s finger, perhaps for life.

Sometimes, as they formed, they turned exquisitely blue, from tiny amounts of boron. A touch of chromium or a dash of other trace elements might transform them into yellow, green, orange, or-rarest of all-red diamonds. The vast majority, pure carbon, metamorphosed brown, dull yellow, and coveted white. Whichever color, they are the most precious substance on earth, not only metaphorically but literally. The famous red diamond sold at auction in 1987 for almost SI million a carat-approximately one-fifth of a gram-made the diamond’s case in spades, pricing it stratospherically above any nuclear isotope, experimental metal, or highly refined drug.

And now you want to buy one for your beloved. Or perhaps for yourself. You want to tap into the source, the heart of creation, the millennia hardened into a practically indestructible stone of glittering beauty.

What to do? What to look for? How much to spend or how little? The mind swims, the heart races.

It’s best to just start at the beginning, whether you’re new to the diamond game or an old but uncertain hand. Diamonds are merely crystals, characteristically six-sided, like two three-faced pyramids stacked base to base. They cannot be grown in a laboratory to gem quality like sapphires, rubies, and emeralds. At least not yet. The larger the diamond, the higher the cost, unless they are of inferior color or have significant imperfections.

In the argot of jewelers, imperfections are called inclusions. All diamonds, because they occur naturally, have inclusions. Some are visible to the naked eye (bad), some are only visible under the standardized 10-powcr loupe or microscope (not so bad). Even those few diamonds graded flawless by the Gemological Institute of America (GIA), the most widely recognized independent grading organization in the United States, have flaws. They’re just smaller than what is visible at 10 times life-size.

All the GIA’s big criteria begin with the capital letter “C, ” and first among them is Clarity, a muy importante “C,” Inclusions affect a diamond’s clarity by impeding the passing of light, and if the diamond can’t transmit light, it will look dim or even cloudy. You must be careful, however, about taking grading scales too literally, even the GIA’s. Diamonds rated SI, or slightly imperfect, should not have inclusions visible to the naked eye, but they often do. You can only be sure of an “eye-clean” diamond when it has a certified rating of VS (very slightly included), VVS (yes, very very slightly included) or IF (internally flawless) . The GIA shies away from the imperious “flawless” grade these days. So many inclusions, yon know, so little time.

If you know someone whose diamond has a visible crack or chip or foreign object in it, this is not good. Most so-called carbon spots, or black specks, in a diamond are really other minerals-garnet, for example. A nice, big clear diamond needs no explanation.

Enough about clarity, except that clear diamonds are rare, and thus expensive. Color is the next step. Diamonds that are whiter, or pleasantly colored diamonds called “fancy” (hues on the color wheel; no neutrals, although grays can be nice), are more expensive than not-so-white diamonds. They are prettier (obviously) and, once again, more rare. There are 23 shades of white diamonds on the GIA scale. Only the first six count. These start at “D” and run to “I.” If it’s a “J” or lower, I’m sorry, it’s a little yellow. (And don’t be tempted to call your mother’s “M”-color diamond a “canary.” It isn’t. Canary is a sloppy name for a fancy yellow diamond.) That’s about it for color. By the way, it’s true: Diamonds can be deliberately exposed to radiation and turn odd colors, like turquoise. This is not terribly kosher, and once in a great while, a little dangerous. Best avoided.

Cut, the next big thing for diamonds, has to do with how the stone is fashioned to bounce light back to your prying eye. Cutting is rarely done with hammer and chisel any longer (“whoops” is a terrible word at a diamond factory). Most diamonds are cut by high-speed saws coated with diamond granules. It may take nine hours with manual supervision to cut a single facet. It’s nearly impossible for a computer to do it well on a good diamond-too much variation from stone to stone.

Cut does not just mean “shape.” Yes, diamonds are cut into different shapes, but having, say, a marquise-cut diamond does not satisfy all your cut questions. Cut is a sticky wicket and, frankly, it’s an issue the GIA ducks pretty thoroughly. A diamond with a GIA certificate does not mean it has been well cut, and it’s very technical to explain how a diamond should be cut. Some GIA gemologist sales-folk blather on about angles and proportions, but what it really comes down to is looks. If a diamond is well shaped to your eye-not too long, not too wide, not coo flat, not too deep- and it sparkles like crazy in natural light (watch out for tricky halogen lighting), without any shady spots or dim places, then it’s probably well cut. Get a scientist chum to measure its crown angle for you later.

And, last but not least. Carat, or weight. The GIA fudges this fourth “C” a little bit. C-A-R-A-T is a measurement of weight, and it’s not to be confused with K-A-R-A-T, which refers to purity of gold. Gems are so light that normal scales are too crude for weighing them, so carats it is. The average engagement ring purchased in the United States has about a quarter-carat diamond in it. If yours is heavier, you did good.

Carat weight is not to be confused with size. A round brilliant-cut diamond looks smaller than a pear-shape diamond because a well-cut brilliant has a bigger bottom than a proper pear-shape. Don’t be fooled by big-looking, broad, flat stones. They fall under the knife of the cut category above, and that cut is bad. Trust me.

That’s about it. The rest is just looking and seeing. As far as settings and jewelry go, you’re on your own. But one word of warning: If all this whets your appetite for diamonds as investments, resist the impulse. Diamonds seem attractive as investments because they’re expensive, rare, and highly desirable. It also sounds great at parties to say, “Yeah, I’m in diamonds.”

But diamonds are only truly valuable to people in the diamond industry and their customers. Unlike pork futures or orange juice or the wheat crop in Alberta this year, they have no predicable liquid value beyond their beauty.

Ask the investment brokers and their minions who got into the diamond game in the early ’80s. They watched diamond prices soar because of their non-jewelry speculation. Then they decided to cash in, and they sold to… each other. This had rapidly diminishing returns. There were no other buyers. Prices crashed. The diamond merchants happily waited until there was nothing left of the market but the whimpering, and picked their stones back up for pennies.

There is no outsmarting the diamond game.

But choosing a shiny princess-cut diamond to grace the third finger of your left hand, or watching the woman you love open that small box across the white-clothed table at The Grape-now that is what diamonds are for.

There’s nothing like a diamond.