NEW YORK (NYT NEWS SERVICE).- After an immeasurable journey through time and space, a craggy gray rock fell to Earth, landing in the Sahara. No one saw it fall and no one knows how long it lay in the sand before it was found three years ago by a nomad.

“It could have been 500 years ago, it could have been 5,000,” said James Hyslop, head of the science and natural history department at Christie’s, which plans to offer the rock for sale at its next online meteorite auction, tentatively scheduled for late summer.

It is a piece of the moon and its recent journey here on Earth — from Northwest Africa to Christie’s in New York, where it and more than 40 other meteorites are expected to be part of the sale — charts the changes in the market for a rare and exotic class of collectibles: rocks that came from outer space.

“The number of collectors is definitely growing,” Hyslop said, “but the number of meteorites is not.”

Meteorites were once the domain of cosmochemists seeking clues about the universe and starry-eyed rockhounds eager to touch other worlds. Value was assigned largely by weight. Only about 60,000 meteorites are known to have landed on Earth, according to experts, but many fragmented into hundreds of pieces as they crashed through the atmosphere, or have since been cut and sliced and cut some more.

“Collectors of every financial means can afford meteorites — it could be as cheap as $5,” said Mendy Ouzillou, vice president of the International Meteorite Collectors Association. He started collecting in 2011 after he was transfixed by a show he chanced upon while channel-surfing: “Meteorite Men,” on the Science Channel. “Sometimes I’ll just open up a box and go through them and when I have time to reflect it still just amazes me where these things came from.”

But it is what these things look like, too, that in recent years has come to determine their value.

“Collecting meteorites is basically three different markets,” said Darryl Pitt, a photographer and musicians’ manager in New York whose interest started when he visited Meteor Crater in Arizona as a boy and who acquired his first one in the 1980s: a piece of the Canyon Diablo meteorite that made that crater. “There are the folks who just want to have a piece of something extraterrestrial and they’re not collectors per se, and there are those who appreciate the science and implications of meteorites.”

And then there are those who regard them as art sculpted by the universe, as he did when he started assembling what he described as “the world’s foremost collection of aesthetic iron meteorites.” (His collection is so broad that it contains not only a piece of the meteorite that smashed through the trunk of a Chevy Malibu in Peekskill, New York, in 1992, but the Malibu itself.)

Some of those — reminiscent of sculptures by Henry Moore and Umberto Boccioni and Alberto Giacometti — were in an auction at Phillips in 1995 that helped ignite this market. Pitt was later a consultant to Bonhams, Heritage and Christie’s when those auction houses entered the meteorite market. Several of his meteorites are in the Christie’s auction.

“These things are going to be looked at for their aesthetic quality as much as for what their inherent value is based on their scientific importance,” said Craig Kissick, director of nature and science at Heritage in Dallas, which sells several hundred meteorites each year through auctions and weekly sales. Its highest sale topped $300,000. “I am comfortable that there is an active market for meteorites in that several-hundred-thousand-dollar range.”

That is the range for the Sahara meteorite that is the marquee attraction in the Christie’s auction, with a presale estimate of $300,000 to $500,000. It weighs about 3 pounds and looks like a miniature moon, but it didn’t fall to Earth that way. It was once part of large chunk of the moon that was blasted into orbit by an asteroid strike and that shattered into pieces when it hit Earth’s atmosphere and scattered across hundreds of miles of what meteoricists call a “strewn field” in Mauritania, Western Sahara and Algeria.

Since it was discovered in 2017, that field has, according to Pitt, almost doubled the world’s supply of lunar meteorites, which stands at about 1,500 pounds. (From 1969 to 1972, NASA astronauts brought back about 900 pounds of lunar material, which is illegal for private citizens to own.) One of those pieces was then hewed into what Hyslop called “likely the largest lunar sphere that will ever be made.”

Cutting a meteorite is not as alarming to a meteoricist as cutting a toe off the Pietà would be to an art historian.

“As long as there is enough material to go around, I don’t have a problem with it,” said Carl Agee, director of the Institute of Meteoritics at the University of New Mexico, who classifies many of the new meteorite finds.

There is a tradition among collectors, museums and scientific institutions of cutting samples and trading pieces, which is how a meteorite from, say, the British Museum might end up in an auction.

“The fact that there is an active market in meteorite buying and selling and also hunting for new meteorites has been beneficial to the science community,” Agee said. “It’s a symbiotic relationship, I guess you could call it.”

The higher prices rise, the more nomads are looking for those odd black rocks that stand out so starkly against the desert sands.

“Meteorites have become like the biggest cash crop for desert nomads,” Pitt said.

And at Christie’s, which has held at least one meteorite auction each year since 2014, they attract more new clients than any other category, Hyslop said, and seem especially popular with younger buyers who “are drawn to these highly sculptural meteorites that also have a cracking good story.”

Like the mind-bending story behind one of the other lots in the auction, a piece of the Murchison meteorite that hit Australia in 1969.

“The actual rock itself formed 4.6 billion years ago, absolutely the oldest material you can actually touch,” Hyslop said. But within it are what he described as “tiny, tiny flecks” that scientists have recently dated to 7 billion years. “Which is nearly half as old as time itself.”

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