It’s not turquoise, it’s not lapis, it’s actually aquamarine.

In “The Devil Wears Prada 2,” Emily Charlton (Emily Blunt) finds fleeting love with Benji Barnes (Justin Theroux), an eccentric billionaire divorcé who showers her with lavish gifts — including a truly spectacular Tiffany & Co. necklace set with an over-31-carat aquamarine and more than 58 carats of diamonds.

“I kind of tortured [the Tiffany team],” the movie’s costume designer, Molly Rogers, told Page Six Style at the launch of her curated “The Devil Wears Prada 2” fashion experience at Printemps New York Wednesday night.

“I wanted to see a lot of necklaces, because that’s how I am. I kept saying, ‘What else you got? What’s in the back room that you’re not showing me? I want to be wowed!’ They had to drag necklaces from all over the world, and I just remember feeling terribly guilty because of the insurance [involved]. These pieces were being hand-carried!”

Rogers was adamant that the bauble featured in the film not be “something that I’d seen on a red carpet before,” to avoid potentially dating the scene. Enter the winning aquamarine masterpiece, plucked from Tiffany’s botanical-themed 2022 Blue Book collection.

“We finally got the right one,” she said. “That blue stone with her red hair — it’s a very, very nice combination.”

As the film’s resident “edgy” dresser, Emily wears everything from Jean Paul Gaultier x Levi’s overalls to a John Galliano newsprint hoodie in the sequel; big, pretty diamonds aren’t exactly her style.

But according to Rogers, there’s a simple explanation for why the character winds up with that gigantic gemstone.

“She’s got a daddy now! Maybe his taste is different,” the costume designer said with a laugh.