World's heaviest diamond dazzles Washington crowds

It's the diamond as big as the Ritz-Carlton, and it's here in Washington. Even F. Scott Fitzgerald, author of the story about the proverbial ``diamond as big as the Ritz'' might have been dazzled by it. The 890-carat Zale diamond, the largest uncut diamond in the world, is sparkling away for a few weeks at the Smithsonian Institution's National Museum of Natural History. The pale yellow stone, mounted on a tall pedestal, will be on display here until Jan. 6, when its owner, the Zale Corporation of Dallas, whisks it away for 18 months of arduous cutting.

The diamond's golden glow draws crowds that press close to see it enthroned in its wood-and-steel Diebold safe at the museum.

``You might think it was just an old Coke bottle or something if you saw it lying in the dirt, until you picked it up,'' says a skeptic in a gray windbreaker. But most of the visitors seem impressed by this rough diamond, textured like a hunk of rock candy, that shines with an eerie, pale gold light. When cut, the Zale could weigh as much as 600 carats, eclipsing the 530-carat Cullinan I, the white diamond of the British crown jewels.

``If cut exceedingly carefully, there is the chance they will produce the largest cut diamond in the world,'' says John White, curator of the gem and mineral collection of the museum. ``You could guarantee that, if it were cut in an asymmetrical free form, removing the [rough] surface and polishing whatever facets'' emerge.

But Mr. White suggests that Zale wants ``a symmetrical stone, one that they don't have to apologize for, a classical cut, and would not be happy with an odd, asymmetrical form.''

Zale is willing to take the chance of a cutting slip that might result in less than a world's record cut diamond, White says, for that classic stone. But he discounts the possibility that a cutting mistake might shatter it to smithereens.

White corrects what he calls the public misconception that such diamonds are hit with a hammer that ``cleaves'' the stone: ``That's not the case; this diamond will be partially sawed with a diamond saw and then actually ground on a circular wheel that has an abrasive on it, bearing down on the diamond to wear away any irregularities in the surface.''

The Zale diamond is flawless, a perfect specimen that contains no carbon inclusions. Among jewelers it's technically known as a ``fancy,'' diamond because of its rare color, which White describes as a ``citron yellow, lighter than the canary yellow found in some smaller diamonds. It has a lumpy angular surface and is going to end up in approximately a pear shape known as a briolette, like a circular pendant that you would expect to see hanging from a chandelier. Its present shape requires that.''

The whole process could take even more than the expected 18 months, Mr. White says, because a lot of deliberate cutting is required.

``The only way you can cut a diamond is with another diamond, which is painfully slow because one diamond doesn't cut another that easily.'' Polishing is also a laborious process, he stresses, as every last scratch must be removed. A New York diamond the size of a walnut once took three months to saw through.

Flanking the Zale at the museum are the 858-carat Gachala emerald -- a shimmering blue-green fire -- and the 423-carat Logan sapphire, a deep, velvety blue stone surrounded by diamonds, which is the largest of its kind known. The gem collection also contains the 7,033-carat blue topaz from Brazil, plus the Rosser Reeves ruby, 138.7 Ceylonese carats of red splendor, and the fabled Hope Diamond.

The Hope sits in a bird's-eye-maple-and-steel safe. At 45.5 carats it is the largest blue diamond in the world. Its color is a murky dark blue, a shade somewhere between French blue and navy. The superstitious legend that the Hope diamond carries a curse has resulted in the museum's receiving a thick file of anxious letters, White says.

``We have a lot of mail from concerned citizens blaming the miseries of the country on the fact that the Smithsonian has the Hope diamond. They believe that such things as the economy turning sour or a threat of war can be blamed on the fact that the US owns the Hope diamond, even though there were two world wars, a Civil War, and a depression before we acquired it. So we don't take that very seriously.''