Paris Hilton's (search) love for Paris Latsis (search) is solid as two rocks — the hotel-heiress hottie is agonizing over which of a pair of stunning diamond engagement rings to choose, sources said Thursday.

Hilton, 24, is torn between two sparklers — a magnificent 24-carat canary yellow ring and a more modest 15-carat white diamond bauble, a source tells The Post.

Each ring is worth between $2 million to $4 million.

The couple made their surprise announcement in front of 75 friends Sunday during a poolside barbecue at Paris' Beverly Hills home.

Since engagement etiquette dictates displaying only one engagement ring at a time, Hilton has been taking turns slipping each rock onto her finger, according to sources.

The Post reported on Tuesday that Latsis, 27, had picked out several possible engagement rings at Harry Winston (search) and Tiffany (search).