ANTWERP, Belgium — Enter, the diamond. A 12-carat white double diamond, crafted out of two raw stones, sat on a black plinth in a glass vitrine in the center of a nearly empty white-walled space in an Antwerp museum.

Next to it, a museum visitor is invited to wear a virtual reality helmet and step inside an enlarged rendition of the same double diamond, and to stand for a moment inside its silent, glittering core.

This is “Melancholia: The Diamond,” a puzzling exhibition created by the Danish filmmaker Lars von Trier, which opened on Friday at the M HKA, the leading contemporary art museum in Antwerp, and runs until May 5.

It was co-produced by Mr. von Trier’s longtime film producer Marianne Slot and Leonid Ogarev, a Russian businessman, who said that it brings together “the oldest material that exists on Earth and an absolutely new material,” virtual reality, which was “so young that you don’t even know how it’s going to be used tomorrow.” Mr. Ogarev paid for the diamond, but he declined to say what it was worth.

The M HKA would not provide photographs of the diamond or allow a photographer from The Times to take any. A spokesman for the museum said that Mr. von Trier insisted on this because “he wants people to come and actually experience it themselves.”

Mr. von Trier said in a Skype interview from his home near Copenhagen that the diamond, which has a brilliant cut on one side but is rough on the other and has the filmmaker’s initials “LvT” carved into it, serves as a metaphorical representation of his 2011 film “Melancholia.”

In the movie, a young woman’s debilitating depression sabotages her wedding night, while a planet called Melancholia hurtles fatally toward Earth. The diamond seems to be a literal interpretation of the film’s apocalyptic denouement: two great stones collide to become a single form.

Mr. von Trier was elusive when asked to explain how the diamond expresses the movie’s essence. “What I’m trying to do is to capture the mood,” he said.

He said he intended to turn all 13 of the films he’s made so far into diamonds and to present them at art institutions across the globe. Mr. von Trier chose to begin in Antwerp, he said, because of its centuries-long association with the diamond trade, and because the city continues to be one of the world’s leading producers of cut diamonds.

The goal of the project, said Anders Kreuger, senior curator at M HKA, is to transform one artistic medium into another: in this case, a film into a tiny sculpture made of precious stone. “He’s created an object of thought rather than an object of entertainment,” he said. “It makes me think about how you can reformulate reality from one form and language into another.”

Mr. Von Trier, 62, who is best known for “Breaking the Waves” (1996) and “Dancer in the Dark,” for which he won the Palme d’Or at Cannes in 2000, is frequently described as a provocateur of European cinema. His sprawling films such the two-part “Nymphomaniac” and his latest, “The House that Jack Built,” feature sadistic violence and graphic sex.

This diamonds project is a departure, and Mr. von Trier admitted he wasn’t entirely sure how it fit into his career.

“It has been in a way a sideline, but you never know where life will take you,” he said. “When it started I thought it would take about two weeks to cut the diamond and it would be interesting.” Instead, it took five years to cut the stone by hand.

The director said he couldn’t travel to Antwerp for the opening, because of ill health and a fear of flying (so severe that he has had to make most of his films in Denmark or Sweden).

“Right now I am trying to get off of these pills so that I can drive again,” he said, explaining that a new law in Denmark bars him from driving while taking certain prescription drugs. He said he was taking “Valium for anxiety, and I’ve been struggling with this since I was seven years old, so it’s a struggle to get off of it.”

Mr. von Trier has been notoriously press shy and somewhat reclusive for years, ever since what he called “an unfortunate press conference” meant to promote the release of “Melancholia” at the Cannes Film Festival in 2011. He jokingly said “I’m a Nazi” and added that he had sympathy for Adolf Hitler.