The frame and images looked old, but there was something about the artwork in the thrift store that struck Wendy Hawkins as remarkable.
So Ms. Hawkins, a volunteer at the Hotline Pink Thrift Shop in Kitty Hawk, N.C., acted on her hunch. She removed the piece from the pile of donations waiting to be sorted and priced, and took it to Melanie Smith, a local art dealer and appraiser.
After a week of scrutiny, Ms. Smith had made up her mind: The piece was a wood block print based on the “Divine Comedy” watercolors of Salvador Dalí, the Spanish surrealist.
“We have no idea who donated it or exactly when,” Ms. Smith, the owner of the Seaside Art Gallery in Nags Head, N.C., said in an interview. “Luckily, it was saved, instead of going by the by,” she said.
The shelves of thrift stores can be places of unexpected discoveries, jammed with everyday trinkets and, rarely, with unexpected treasures. In the 35,000 resale stores in the United States, the occasional lucky customer can find an item of value — usually antiques, jewelry or artwork — among the castoffs.
This appears to have been the case with the mysterious piece Ms. Hawkins found in North Carolina, where donations are dropped in bins or at the doors of five thrift stores affiliated with the Outer Banks Hotline, which supports domestic violence victims.
“We usually price things like ‘cookie-cutter’ art for condos that could go for $10,” said Michael Lewis, the executive director of the hotline.
Ms. Smith said the piece was given to her to examine in January, but the story took off, Mr. Lewis said, after it was put on display and the local news media reported on the find last week.
“Now people come in and say, ‘Where is your art section?’” he said.
Ms. Smith, a member of the International Society of Appraisers who usually works directly with artists, estates and auction houses, said it was the first time she had appraised a piece of art from a thrift store’s donation pile.
The piece is based on a series of watercolors Dalí made to illustrate “The Divine Comedy,” a work by the Italian poet Dante Alighieri in the 14th century. Dalí’s work was first commissioned by the Italian government in honor of the 700th anniversary of Dante’s birth.
But the project was dropped after an outcry in Italy that a non-Italian had been given the job. So the series of watercolors was taken up by the French publishers Joseph Forêt and Editions d’Art les Heures Claires de Paris.
When Dalí, who died in 1989, finished the project, he had completed 100 watercolors for the poem’s 14,233 lines: 34 illustrating Inferno, 33 illustrating Purgatory and 33 illustrating Paradise.
Then, over several years, artisans carved 3,500 wood blocks to make prints of the original watercolor illustrations for the book, which was published in the early 1960s. Some of those prints required up to 37 individual blocks to impress each of its colors of ink, one at a time.
“At that time Dalí was doing not just single prints, but he was doing elaborate printing books,” said Joan R. Kropf, the director and curator of collections at the Dalí Museum in St. Petersburg, Fla.
Over the years, some single prints would appear. “And where they came from was a question,” she said. “Some were sold individually.”
Some of the prints had signatures in colored pencil, Ms. Kropf said — purple for purgatory, blue for heaven and red for hell. Dalí signed 150 sets of prints in colored pencils in New York City in the 1960s or 1970s at a gallery on Madison Avenue and at the St. Regis hotel, where he was a frequent guest, she said.
Frank Hunter, the director of the Salvador Dalí Archives, an authentication service, said that people and dealers often buy sets of these wood block prints at auction and sometimes sell them individually.
“Most were not signed, but a few years after their publication, Dali did sign a number of sets in colored pencil,” he said.
Mr. Hunter said that there are at least 950,000 wood block prints based on Dalí’s “Divine Comedy.”
“Some of this is a lot of detective work,” he said.
Dalí was one of the most widely copied artists of the 20th century, and he sometimes signed blank sheets of paper for money. Works linked to him have surfaced in a thrift shop before. In 2009, customers at a Salvation Army Family Thrift Store in Houston bid on drawings attributed to Dalí despite the ubiquity of fakes and the uncertain provenance of those pieces in particular.
Ms. Smith said the wood block engraved print that she examined from the thrift store in North Carolina was derived from Dalí’s Purgatory 32 watercolor. It had Dalí’s signature, she said.
She said it was difficult to authenticate the piece. Ms. Smith consulted the “Official Catalog of the Graphic Works of Salvador Dalí,” which was self-published in 1998 by Albert Field, whom Dalí designated as his official archivist.
Mr. Field, who died in 2003, got to know some of the many forgers who were drawn by Dalí’s easy-to-replicate signature and by his immense output, which made single copies hard to pinpoint.
When it comes to art in the wild, the stakes for authenticity and origin can soar. Experts spend years studying individual artists to differentiate between forgeries, reproductions and one-of-a-kind works that can sell for millions of dollars.
Adele Meyer, the executive director of the Association of Resale Professionals, said thrift store donors often do not know the value of the pieces they are giving away, particularly if they inherited an item or found it in storage. “If they didn’t have an eye for it, or experience, they wouldn’t even think to check,” she said.
Ms. Smith used a 10-power magnifying loupe to examine the discovery at the thrift store in Kitty Hawk, picking up the color pressed to the paper by the wood block. She raked a light across the back of the paper, looking for slight indentations from the press.
“When you look at it under the loupe you can see the way the colors are laid on top of each other,” she said.
After she purchased the piece from the thrift store and had it reframed, Ms. Smith sold it for $1,245.
“I would be in a thrift store every day if I thought I could find something like that,” she said.