At the turn of the 20th century, Louis-François Cartier’s three grandsons propelled the eponymous French luxury house to international prominence. And of this trio, Louis Cartier oversaw what today might be deemed new product development: The eldest grandson encouraged the adoption of platinum as a jewelry setting and invented the men’s wristwatch in 1904.
Eight years later, when presented with a so-called mystery clock by watchmaker Maurice Couët, Louis, ever the trend forecaster, added these timekeepers to the Cartier lineup. On Wednesday, one of these rare pieces—and the only known mystery clock that incorporates rhodonite—will be available for sale from the French auction house Piasa.
Mystery clocks derive their name from the rock crystal disc to which minute and hour hands are attached, and which hides a rack-and-pinion system. The hands appear to rotate without the assistance of any movements, in turn.
While Couët did not conceive the horological sleight, Louis Cartier elevated it to a thing of status. Fabrication of a Cartier mystery clock took place over 12 months, requiring the expert touch of a goldsmith, an enameler, a lapidary, a setter, an engraver, and a polisher, and the mechanics were kept secret even from company staffers.
For consumers, meanwhile, owning a mystery clock “was a way for the owner to declare that he was rich and powerful,” says Salomé Pirson, a specialist in Piasa’s department of jewelry and watches. “Possessing one was something that people would remember forever.”
The mystery clock up for auction is related to Cartier’s portico design, which was the last style produced before production was interrupted in 1931. The object includes a single-axis mechanism, which Couët began employing in 1920. The rhodonite is combined with onyx to evoke the skyscraper architecture of the Art Deco movement. According to an essay by Olivier Bachet and Alain Cartier that Piasa had commissioned for its catalog, mystery clocks of similar vintage often incorporated rose quartz. This example, then, was probably a special order. It was last owned by the family of legendary auctioneer Maurice Rheims, who died in 2003.
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Compared to the booming market in wristwatches, Pirson says, competition for table clocks and similar precious objects is steady. Even so, mystery clocks are commanding increasingly strong prices. Piasa’s estimate for Wednesday’s sale begins at $485,000, and sales at Christie’s and Sotheby’s have resoundingly trumped that figure as recently as December.
Pirson characterizes interested buyers as collectors of Art Deco–era furniture and decorative arts, for whom the mystery clock would provide the finishing touch on an immersive environment. She also anticipates interest from Cartier fans, horologists, and museums. Although bars and restaurants reopen in Paris on Wednesday, Piasa will conduct the auction entirely online. The digital sales platform is available by registration.