Museums: Precious Gems of the Deep

The ancient Greeks thought pearls were created when lightning struck the sea. Other peoples of antiquity attributed pearls to rain-drops or dewdrops, captured and solidified by clams. But it was another classical civilization whose theory most poignantly captured the romance of these gems, one of human-kind's oldest. Pearls, concluded the Romans, are the frozen tears of oysters--or of the gods.

In the most comprehensive exhibit of pearls ever mounted, the American Museum of Natural History in New York explores the history, science and lore of the only gems that come from living creatures. Dedicated "to deepened cultural understanding and peaceful co-existence" in the wake of the terrorist attacks, the show--through April 14 of next year--suffered some blowback from Sept. 11. The Kremlin withheld a couple of pieces, the Louvre decided not to send Empress Josephine's pearl earrings and scrambled flight schedules delayed the arrival of some pieces (Liz Taylor's 10-gram, pear-shaped La Peregrina arrived just in time). But with 800-odd objects, including the necklace Joe DiMaggio gave Marilyn Monroe on their honeymoon in 1954, and 500,000 individual pearls from (among other countries) Venezuela, India, Tahiti, Japan, Germany, Monaco, France and England, the absences hardly show. "An exhibition about these extraordinary objects, which reveals the vitally important intersection of science and culture, is especially appropriate at this time when we are all endeavoring to better understand one another and the world around us," says museum president Ellen Futter.

Pearls have financed wars and sealed wedding engagements, and topped the "bring back" list that Queen Isabella and King Ferdinand of Spain gave Columbus (a priority higher than their order for gold, silver and spices). He obliged. During his third voyage to the New World, in 1498, Columbus stumbled on a cornucopia of natural pearls off the coast of Venezuela, near the mouth of the Orinoco River. The discovery of this "Pearl Coast" touched off a pearl rush that flooded Europe with these natural gems for the next century and a half. The luminescent jewels became unrivaled as symbols of wealth and power during the Renaissance.

Because faceting technology for precious stones was not developed until the mid-17th century, the royal and fashionable dripped not with rubies and diamonds but with pearls. By one estimate, in the early 1500s Spain alone imported, from one site on the Pearl Coast, more than 118 million pearls. From the jewelers and merchants of Seville the gems made their way throughout Europe and into Asia; many of those are on display at the show (which travels to Chicago's Field Museum next June). The pearl-and-gem brooch that Prince Albert presented Queen Victoria on their third anniversary dazzles. Also in the exhibit is a 177-pearl necklace given to the duchess of Saxony in 1802 and a replica of the largest known pearl: a 14-pound specimen that looks like a human brain glowing in the twilit rooms. Portraits of Queen Elizabeth I and of Sir Walter Raleigh show that pearls did not play gender favorites: both are bedecked in pearl-embroidered finery.

Not bad for mineralized deposits in soft tissue. Pearls are, in essence, the kidney stones of the mollusk world. They form when a foreign object (usually a parasite, sometimes a tiny fish or snail, almost never the proverbial grain of sand) becomes lodged between a mollusk's shell and its mantle, a specialized tissue that lines the inside of the shell. The mantle coats the object with thousands of concentric spheres of calcium-carbonate crystals called aragonite. Pearls also contain proteins from the mantle, as well as trace elements from the water, which can turn them black, blue, silver, cream, pink or dove gray.

All mollusks (even the lowly snail) are capable of producing pearls, but only a few produce gem-quality specimens. Those made by edible oysters, for instance, are just dull little beads resembling white marbles and good only for cracking a tooth. Mollusks have been in the pearl business for a while: fossil pearls are abundant in 60 million-year-old rocks. The gems seem to glow from within because light penetrates the surface and reflects off the inner layers. But then, you would expect luster to be a trait of the Gods' tears.