Few guests at first notice the seven small stones, shimmering icily in the corner of this Ginza reception hall. The little shards catch a beam of light for the briefest instant, before flicking it gaily away.

Who but a connoisseur could imagine that these seven tiny rocks possess a combined value of nearly $4 million? Or that objects of such delicacy could be crafted from the hardest natural substance known to man?

The crowd finally notices the diamonds and, suitably impressed, turns to toast the man who gave them their glitter, renowned Belgian diamond-cutter Gabriel Shraga Tolkowsky. Sixty-two-year-old Gabi, as he is known, is so skilled at reducing rough stones to geometric perfection that one industry insider called him "the god of diamonds," an artisan who bewitches -- and is bewitched by -- each gem he touches.

"Multiple mirrors -- on the diamond and inside the diamond. All of this together is bringing you to the emotion which we call beauty," mused Tolkowsky, the sixth-generation diamond-cutter in his family, who was here earlier this month for the opening of his first collection in Japan.

Japan, the world's second-largest diamond market after the United States, has few experienced diamond-cutters of its own. For Tolkowsky, however, the seven diamonds over in the corner were mere child's play. He's best known for having cut the Golden Jubilee that rests atop the scepter of the King of Thailand. It's bigger than a fig and, at 545.65 carats (109.13 grams), it's said to be the world's largest cut diamond. Tolkowsky also crafted the 273.85-carat Centenary commissioned by the Diamond Trading Company (formerly De Beers) and unveiled in 1991 to commemorate their 100th anniversary. The flawless, 247-facet gem is, he says, rumored to be insured for about $100 million -- though he insists he doesn't know its actual value or current owner.

In cutting diamonds -- whether the craftsman is Tolkowsky making lapidary history in Antwerp, a technophile in Tel Aviv employing a laser, or a smith in Mumbai relying on the traditional blade and hammer -- the goal remains the same: to produce contours in the diamond that trap light inside and sparkle. It's all a matter of technique.

A cutter begins with a rough diamond that resembles a chunk of rock candy, inspecting it through a magnifying glass for flaws such as inconsistencies in crystalline structure that can cause it to shatter during processing. Sometimes, the cutter divides an unwieldy stone into workable parts by lowering it over a circular saw spinning at almost 10,000 rotations per minute. Ground-diamond powder is applied to fortify the edge of the metal blade, which would otherwise be useless against the harder gem.

In the next step, the characteristic mirrorlike planes, or facets, are ground into the gem by applying its surface to the side of a spinning plate, also treated with powdered diamond. The cutter then places the semifinished jewel on a revolving spindle and uses a tool tipped with a low-grade diamond to round off any jagged edges. Almost done, the gem is again put to the grinding plate to create further facets, and then it receives a final polish. An acid bath removes residual grease and dirt, and voila! -- the diamond is ready for mounting.

Throughout this process, the craftsman must carefully avoid the diamond's internal weak spots -- one wrong move could destroy not only a million-dollar rough but also the career of its handler. The more deftly a diamond is cut, the more light is refracted from its top and sides, creating stronger concentrations of both colored light and white light -- known in the parlance of diamantaires as "fire" and "brilliance."

The price of a finished diamond is determined by the "four Cs": cut, clarity, color and carat. Buyers can choose from a global range of more than 100 shapes and a wide variety of hues. For example, a Brilliant-style diamond -- domed on top and pointed on the bottom, with at least 58 facets in total -- refracts the most light and is a favorite for engagement rings. Women opting simply to treat themselves, however, might instead select a long and narrow Marquise, which makes fingers look slim.

Cutting and polishing a 1-carat sparkler takes approximately 12 hours from start to finish, according to Nizam Peters, director of the Florida-based American Institute of Diamond Cutting. But Tolkowsky and his team of technicians took three years to complete the Centenary, during which the master cutter often dreamed about the gemstone, in his reveries seemingly able to "to ask [it] questions and get answers" on where to cut.

The years of hard work paid off, said Tolkowsky: He calls his masterpiece "the most fabulous diamond in the second half of the 20th century."

While Tolkowsky is a celebrity in his own right, few of the artists who fashion diamonds enjoy such recognition, complained Martin Fainberg, a cutter for 33 years in New York's diamond district in midtown Manhattan. Indeed, the working conditions of most artisans are far removed from the glamor of their creations. Many diamond-cutters are self-employed, which often means little vacation time, personal responsibility for retirement and health provisions -- and the need to seek out their clientele.

To make matters worse, the worldwide economic downturn has seen customers become more picky, demanding top-quality gems at bargain prices. And with competition from low-wage countries, it's increasingly hard for diamond-cutters in Europe and America to eke out a reasonable living.

To this can be added the risks inherent in dealing with one of the world's most coveted luxuries. Companies that trade in precious stones are on constant alert against theft. Anyone who sets foot in a diamond workshop falls under the scrutiny of close-circuit cameras in the elevator, the hallway -- everywhere. Some studios are even said to X-ray the shoes of departing visitors to check that no stone has been filched.

So depite the glitter and glamor of the gemstone world inhabited by such as Tolkowsky, for many diamond artisans life lacks the sparkle of their creations. "I'm very stressed out," confesses Fainberg. "I'd rather go work for the post office. If I'd worked there, I probably would have retired by now."