Towering above you, his sinewy arms will stretch out for crucifixion. His glowing body will convulse sporadically, shooting off showers of golden embers.

But this isn't the second coming -- it's a piece of virtual reality art by the German-Danish artist Christian Lemmerz.

Titled "La Apparizione" (The Apparition), the artwork will be presented in an empty three-by-three-meter room. Viewers step inside, slip on a VR headset and are transported into outer space, where they can circle the levitating, golden Jesus.

It is one of two virtual reality works being exhibited by the Faurschou Foundation in Venice this summer. The gallery joins a growing list of institutions that have exhibited VR art, including New York's Museum of Modern Art and the Whitney Museum of American Art.

And as the world's top curators embrace this new medium, collectors are starting to circle.

You might not be able to hang "La Apparizione" on your wall like a painting, but it is most definitely for sale. Lemmerz has released five editions, each costing around $100,000.

But valuing virtual art poses a new a challenge for buyers and sellers alike. Galleries normally look to artists' previous work when setting prices, but with only a small number of VR artworks on the market, there are only a few precedents to refer to.

Comparisons with other types of art do not always prove useful. Lemmerz is primarily a sculptor, but can "La Apparizione" be compared to his 2013 bronze sculpture of Jesus?

The latter work is an object, the former an experience. And while artists have been making bronze sculptures for millennia, virtual reality is a brand new technology more familiar to gamers than art collectors.

The market is still adjusting, according to Sandra Nedvetskaia of Khora Contemporary, the production company that helped Lemmerz create his latest VR art.

"At the moment, video art works are the only comparison," she said over the phone. "But (some collectors) have likened (virtual reality artworks) to sculptures because, of course, you find yourself in the middle of that particular artist's moving sculpture."

Hardware is another new consideration for galleries, and those selling VR art often include a headset in the price. Nedvetskaia said that all works produced by Khora Contemporary come with HTC Vive headsets -- and a lifetime service.

"That includes updates," Nedvetskaia added, "so that this artwork doesn't become (like) a video tape that you can no longer experience."

But the speed at which VR technology is changing can be a problem for artists, according to Edward Winkleman, who co-founded of the video-oriented art fair, Moving Image, in 2011.

"Whether they should wait for the hot, new head-mounted display is a constant question in their practice," Winkleman says. "If they wait, they can take advantage of the new upgrades. But they may (also) miss an opportunity to present their work."

Young artists are experimenting with virtual reality -- and not all of their works carry the six-figure price tag of "La Apparizione," according to Murat Orozobekov, the other co-founder of Moving Image.

Notable VR works at this year's fair included a swirling, psychedelic piece by up-and-coming digital artist Brenna Murphy, and "Primal Tourism: Island," which took viewers inside Jakob Kudsk Steensen's dystopian vision of a Polynesian island.

"Prices range from about $2,500 to $6,500 for an emerging artist's work," Orozobekov said over the phone.

At the other end of the market, a disturbing VR piece by American artist Paul McCarthy is currently available at two major European galleries -- Hauser & Wirth and Xavier Hufkens -- for approximately $300,000. Set in a lurid room, the work features a group of female characters who taunt each other, and, occasionally, the viewer.

The difference in asking prices is not simply a matter of reputation, according to Elizabeth Neilson, director of The Zabludowicz Collection in London.

"(There's also) the development costs of the technology they have used. Someone like Rachel Rossin does a lot of the development herself, but someone like Jordan Wolfson does none of the technological work himself, and outsources to Hollywood professionals," Neilson said, referencing two up-and-coming artists who have been working in virtual reality. "As you can imagine, this is expensive."

The price of virtual artworks can be kept high by limiting the number of copies made. McCarthy's VR piece was only released in an edition of three, and Lemmerz's in an edition of five.

By deliberately restricting supply, galleries create a market for virtual reality art that is based on scarcity -- as with paintings and sculptures. But unlike other art, virtual reality pieces are infinitely replicable. In their most basic form, they are simply digital files that can be experienced by anyone with a VR headset.

While an artist can easily limit the editions of a sculpture, it is much harder to curb the spread of a digital file -- something that the music and movie industries discovered the hard way. But this presents opportunities as well as threats, according to Nedvetskaia.

"In five years' time every single one of us might have a set of virtual reality goggles in addition to our iPhone," she said. "So don't rule out the possibility that editions of virtual reality artworks might be made at an affordable price so the public can view them. We're really on the cusp of this market being born right now --the possibilities are limitless."

The art world establishment is yet to fully embrace digital art. Neither Christie's nor Sotheby's have sold a VR work. But both have expressed cautious interest in the medium.

In March this year, Sotheby's became the first major auction house to exhibit virtual reality art. Hosted at its New York headquarters, the technology-focused exhibition "Bunker" featured "La Apparizione" and a VR work by Sarah Rothberg called "Memory/Place: My House."

Christie's chief marketing officer, Marc Sands, believes that it is only a matter of time before VR starts appearing at major auctions.

"Response to (virtual reality art) from both consignors and buyers is largely positive but to date we have not discovered the 'killer' version of VR," Sands said. "However, as with many things digital, it will come sometime soon."

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