“Geneva is just a natural step,” said Stephen Brooks, the chief executive of Phillips auction house, best known for buying and selling art and design. “We’re signaling to the marketplace that we want to be significant in this space.”

On Nov. 6, Phillips has scheduled the first of what it said will be twice-yearly jewelry auctions in the city, held in May and November. These are the periods when important trade shows and other jewelry auctions fill the luxury hub, in much the same way events are held in style capitals during Fashion Weeks.

In recent years Phillips has held jewelry auctions in Hong Kong and New York, and has said it will continue to do so. But the decision to add Geneva, made early this year, seemed to be supported by recent successes: the $1.15 million auction in June of a collection of jewelry from the estate of the Tennessee architect Earl Simcox Swensson and his wife, Suzanne D. Swensson; and the $3.42 million sale in May of a 118.5-carat sapphire and diamond necklace by Bulgari.

Mr. Brooks said the additional location “is very much a sort of statement of strategic intent” and that he wanted “our jewelry business to be as big and impactful and successful as our watches business,” which debuted in 2015. That department almost instantly grabbed headlines by collaborating with Aurel Bacs, the star auctioneer, and then orchestrating the $17.8 million sale of the Paul Newman’s Rolex Daytona in 2017.

“I looked at our jewelry business,” Mr. Brooks continued, “and said, ‘Well, it could be the same,” because “it’s talking to this new audience that we talk to, very much more diverse, very much more sort of younger audience and a global audience.”

David Brough, editor and publisher of the trade website Jewellery Outlook, wrote in an email that “Phillips’s decision to join the Geneva auctions is a challenge to Christie’s and Sotheby’s for market share at the top end of the jewelry market.”

To guide Phillips’s strategy, Benoît Repellin was named worldwide head of jewelry in March.

“We have already quite a few interesting items,” Mr. Repellin said of the debut auction. One highlight will be contemporary works, in a bid to make the sale more distinct, he said, with pieces by Silvia Furmanovich, Viltier and Margaret.

Other highlights, he said, will be signed jewels by Cartier, Chaumet and Boucheron, and a 15.6-carat diamond ring with a sales estimate of $500,000-$800,000 and a 1950s Van Cleef & Arpels sapphire and diamond bracelet with a sales estimate of $100,000-$150,000.

“I think,” Mr. Repellin said, “where we can also make the difference is really bringing jewelry to the market because when you look at some auctions, it’s a lot of stones.”

And while stones are important, he wrote in a later email, the auction house “would like to also offer some jewelry collections and important jewels that speak to collectors.”