Diamonds catch the light and return it as a wink -- flashing "go," "stop," "caution." Jewels seduce, lure, entrap. Precious stones empower the wearer, magnetize the unsuspecting victim and keep secrets to themselves.

A hundred bejeweled objects of such potency from the atelier of Van Cleef & Arpels are on view in a nook near the blue Hope diamond in the Gem and Mineral Hall of the Smithsonian's National Museum of Natural History. The exhibit, "A Jeweler's Art: Masterpieces From Van Cleef & Arpels," was previewed Thursday night at "A Gem of an Evening." A hummingbird clip, donated by Van Cleef & Arpels, was auctioned for $25,000 to an undisclosed buyer. (The profits from the auction and ticket sales will go toward the $10 million to $12 million estimated cost of remodeling the museum's Gem and Mineral Hall.) The exhibit (which began at the Los Angeles County Museum of Art in April) will stay through Nov. 30 and then go on to the Honolulu Academy of the Arts Jan. 16.

Many of the jewels come from a very private collector in New York, said Larry French, Van Cleef & Arpels vice president. "We'd be glad to give his name, but he doesn't want it mentioned." Obviously! The others are a part of VC&A's own hoard.

Whatever their provenance, jewels acquire a patina of history as their sparkling lives progress. The best of these pieces were designed in the 1920s and '30s, in the style properly called art moderne, but more recently nicknamed art deco. A few less interesting works are from the 1940s.

A three-inch peony, of platinum, diamonds and rubies -- made in 1937 in the serti invisible technique -- is perhaps the most dazzling piece. The edges of the stones are grooved precisely (within a hundredth of a millimeter) to slide into the metal tracks of the setting. Some pieces, French said, took two years to make. "I doubt we could make one now." Of this magic manufacture are a mid-1970s double flower; two bracelets both of platinum and diamonds, the 1983 one with rubies, the 1937 with sapphires; and a 1954 platinum, diamond and sapphire clip.

The essence of art moderne's geometric design is well exemplified in a 1931 brooch, fashioned of baguette, half-moon, and trapezoidal diamonds and brilliants set in platinum. A gold and diamond zipper, commissioned by one client to actually open and close dresses, also served as a necklace. A tiara, once owned by Princess Grace (Kelly) of Monaco, started out life as a necklace. Several pieces can be reassembled as clips, brooches, necklaces, etc.

Precious stones, no matter how brilliant, can be eclipsed by the magnificence of a design, as in the case of the exquisite Japanese Temple Portico Clock -- actually an art moderne timepiece. Of course, art moderne owes much to the Nippon islands, but this work could only have been designed in Paris of the 1920s. The clock set a world record at a Christie's auction on May 19, 1979. (The clock brought 1.7 million francs, but it's difficult to calculate just how much that would be in today's dollars.) Two crystal columns support a gold cross bar; the gold and onyx clock case frames a crystal dial. Time is told not with numbers but with the enameled signs of the zodiac framed in diamonds.

Minute watches are also intriguing -- the 1931 "radiator" watch has small closeable blinds on its face. The padlock watch is made of platinum and diamonds. On a 1925 watch, Buddha's hands point to the time.

A remarkable night light is fashioned of gold, rock crystal and enamel. Jade cigarette holders were designed to be placed at each diner's plate.

The minaudieres are in many ways the most fascinating objects. The cases, substitutes for evening bags, are said by the book "Van Cleef & Arpels" by Sylvie Raulet, to be so called because Estelle Arpels Van Cleef was adept at minauder. Raulet translates the word as "to simper" but more likely, minauder is a form of flirting more properly described as "are you really attracted by little me?" The cases often come fitted with all sorts of ne'cessaires -- lipstick cases, powder boxes, even a tiny pair of opera glasses. In the exhibit also are cigarette boxes, vanity cases, powder boxes and some boxes hard to identify -- set with jade, diamonds, rubies, sapphires, pearls, etc.

A 1930 vanity box, for reasons that have been forgotten, has a tiny car and train racing across its front, put together of platinum, diamonds, sapphires and emeralds. Others are decorated with a Chinese landscape, a bird, flowers or a hunting scene. Sometimes a lipstick is attached on the outside. An especially lovely 1928 powder compact is bedecked with polished lapis, fluted rock crystal, turquoise cabochons (unfaceted stones) and brilliants (multi-faceted diamonds) set in platinum.

The Iranian crown is in a case by itself, though it is but a copy -- its structure only silver, its diamonds simulated, its colored stones glass, its pearls faux. French said that the original (presumed locked in a vault in Tehran -- but who knows?) is "the most important commission" the jewelers have ever had. Pierre Arpels was invited in October 1966 to submit designs for a crown for the coronation (the first for an Iranian empress) in 1967 of Farah Pahlavi. Arpels won the competition, only to learn the crown was to be set with jewels from the Iranian collection -- so precious they would not be allowed out of the Central Bank of Iran's vaults.

"Pierre Arpels traveled 24 times to Iran to make the design," French said. His trips were worth the trouble. A 150-carat emerald was set as the headlight of the 1,541 stones -- 1,469 diamonds, 36 rubies, 36 other emeralds -- and 150 pear-shape pearls. The crown took six months to make and weighed 1,950 grams.

French characterizes VC&A jewelry as supple, elegant and classic. The first of the firm was a gem cutter, Charles Van Cleef in Amsterdam. He moved to Paris in 1867 and thus began the dynasty. His son Alfred married a cousin, Estelle, daughter of precious stone dealer Leon Arpels. Her brothers became partners. At the turn of the century, the firm moved to 22 Place Vendome. The firm now has a showroom and workroom in New York, as well as a workroom in Los Angeles and a Palm Beach showroom. VC&A spokeswoman Nina Wahl said 80 percent of the jewelry sold in the United States is made here and a similar percentage made in the Paris workroom is sold in France.

In the past few decades, Wahl admits, the firm has become more conservative than in the adventurous design days of art moderne, limiting its stones to diamonds, sapphires, rubies and emeralds, with only an occasional mad venture with yellow diamonds or pearls. But as the century swings to the millennium, rumbles can be heard in the workrooms, and who knows what marvels will come forth.