GREEN DREAMS.(emerald earrings of Elizabeth Farnese)

Fred Leighton, the jeweller, is situated on the northeast corner of Madison Avenue and Sixty-sixth Street. The ornate awning, window frames, and door are polished brass--from the outside the shop looks like an outsized brooch set with precious stones. The jewels in the window displays, arranged on gray suede shelves, change regularly, but on any given day their value is upward of twenty million dollars. Almost all of them are rare and old, and, either a lifetime or five minutes ago, belonged to someone who loved them. Most of them are currently loved, some passionately, by Fred Leighton himself. But Leighton, who, at seventy-two, looks more like an aging jazz producer than like one of the most important jewellers in the world--he favors sharkskin suits, and his graying hair hangs in points almost to his shoulders--usually wears only one jewel himself: a discreet lapel pin in the shape of a jockey. The jockey's cap is made of eleven tiny diamonds, and his body, the size of a cat's eye, is a shining moonstone. Like all the best gamblers, Leighton trusts his instincts.

Jewels have not loomed large in my life. Nevertheless, during the late spring and summer of this year I found myself at Fred Leighton staring with a certain amount of desperation at a pair of emerald earrings. They were three and a half inches long. Pear-shaped emeralds, set in borders of green-tinged gold, descended in tiers. There were thirty-eight absolutely clear blue-green gems in each earring, and the two central briolette emeralds weighed fifteen carats apiece. The stones made me think of crocodile tears.

The emeralds were part of a set. There was a gold handwrought pendant containing forty-five square-cut, shield-shaped, and briolette emeralds; two cluster rings, with, respectively, nineteen and twenty-five emeralds, totalling 15.4 carats (there was a small hole in the band of each ring so that it could be sewn onto the finger of a gauntlet glove); and sixteen buttonlike links, each made up of six step-cut and three oval, briolette, or round emeralds. The three hundred and nine emeralds in the set total 232.64 carats.

The jewels looked as if they were meant for a queen, which I was not. As I gazed at the emeralds, I understood, for the first time, the lure of jewels, and I recognized in myself the stirrings of lust and avarice. When I finally gathered my courage and asked if I might handle them, one earring covered my palm. It was too big to hide when I closed my fingers.

In May, when I first saw the emeralds, Fred Leighton and his staff, including Rebecca Selva, a striking woman from El Salvador, who handles clients who on Madison Avenue pass for royalty (Nicole Kidman, Sarah Jessica Parker), believed that the earrings had been meant for a queen: Elizabeth Farnese, the plain, long-nosed niece of the Duke of Parma. In 1714, at twenty-one, Elizabeth married Philip V of Spain, who was thirty. After the marriage was consummated, on Christmas Eve, Philip declared himself Elizabeth's "slave for life." The Queen developed a reputation for intransigence; the King was given to melancholia. Philip also had financial problems: the recently concluded War of the Spanish Succession had cost Spain many of its territories, and while for two centuries the Spanish court had been enriched by the fleets, composed of several dozen ships, that sailed annually to the New World, only a few ships had sailed from 1702 to 1711. That Christmas, the King was awaiting the return of a fleet that would replenish his coffers and furnish his new queen with jewels.

The Galeones de Tierra Firme fleet had set sail for Colombia, to pick up jewels from the Muzo and Chivor emerald mines, in the dense jungle region north of Bogota. By 1567, the Spanish had wrested control of the mines from the Muzo Indians, who had kept their location secret for centuries. They forced captive Indians to work the mines until, by the beginning of the eighteenth century, harsh labor conditions and disease had decimated the population. "Muzo and Chivor produced the finest emeralds in the world," Rebecca Selva told me when I visited Fred Leighton. "The mines are fabled. These beautiful things come out of a very dark period of Latin-American history."

In September, 1714, the Galeones fleet sailed to Havana, and waited there for the New Spain Flota, which had left for Mexico in 1712 with orders for textiles and porcelain from the Far East (sent overland through Veracruz), as well as for gold, silver, and jewels. The boats also carried newly minted currency, cocoa, vanilla, paper, brazilwood, and animal hides. The official manifests, sent ahead to Spain, did not account for all of the goods on board: twenty per cent--the "Royal Fifth"--would be claimed as taxes, and many merchants bribed officials to underestimate their cargo. According to the ships' manifests, General Don Juan Esteban de Ubilla, the captain of the New Spain Flota, carried treasure for the Queen on the lead ship, La Capitana.