NEW YORK, United States — Harry Winston made the winning $50 million bid for a pink diamond at an auction by Christie's, setting a record price for price paid per carat for a gem of that hue.

The 18.96-carat stone was the largest fancy vivid pink diamond ever offered at auction by Christie’s, and comes from the collection of the Oppenheimer family, the former owners of De Beers. It sold after five minutes of bidding, meeting the high estimate. The luxury diamond purveyor renamed it the Winston Pink Legacy.

The sale sends a signal that demand for the rarest diamonds is faring better than the bottom end of the market. De Beers cut prices of low-quality stones by as much as 10 percent at a sale this week, according to people familiar with the situation. The price for the latest acquisition was $2.7 million per carat, beating the $2.2 million record that was set by the Pink Promise in a Hong Kong auction last year.

This isn’t the first time Harry Winston has splashed out on such a rare diamond. The luxury jewellery maker, which Swiss watchmaker Swatch Group AG acquired in 2013, paid $27 million for the 101.73-carat colourless Winston Legacy diamond at a Christie’s auction that year.

“We are proud to continue in the Winston tradition of acquiring the finest gems in the world,” Harry Winston chief executive officer Nayla Hayek said in a statement.

The autumn auction season is under way in Geneva. Sotheby’s will offer jewels that once belonged to Marie Antoinette on Wednesday evening, including an 18th-century natural pearl and diamond pendant that’s estimated to sell for as much as $2 million.

By Corinne Gretler; editors: Eric Pfanner, Thomas Mulier, John J. Edwards III