AUGUSTA — Savannah River Site historian George Wingard’s fascination with the slave potter known as “Dave” began with a phone call in 2006 and led to an upcoming film honoring one of the South’s most mysterious artisans.

“That morning, we had people looking around in an area where some monitoring wells were planned,” said Wingard, the administrative manager for the Savannah River Archaeological Research Program, whose workers are required to evaluate areas to be disturbed by construction.

As routine, random test holes were dug to determine whether any important artifacts might lie beneath the soil, the technician discovered the proverbial needle in a haystack: a large, greenish-glazed shard of stoneware pottery.

“When he pulled it out, it had ‘Dave’ inscribed on it,” Wingard said. “He called me right away, from his cellphone.”

Both men knew immediately the find was an important one.

Dave was a slave who worked among the dozens of potteries that operated during the 1800s throughout South Carolina’s plantation-strewn “Edgefield District” near Augusta.

The region’s alkaline-glazed pottery is widely sought by art collectors, but the works of the mysterious Dave are the most prized examples of all. Further excavation at the remote hillside within the Savannah River Site yielded more pieces of Dave’s handiwork.

“We were digging in what turned out to be a mid-20th century trash pile,” Wingard said. “We found about 95 percent of the jar.”

In addition to Dave’s signature, the jar — which was carefully reassembled — carried the date of manufacture: April 16, 1862. Soon it became a popular item in the research program’s outreach activities, which include educational programs to acquaint others with the region’s cultural past.

Wingard’s interest in Dave’s legacy expanded. He soon teamed up with Augusta filmmaker Mark Albertin, of Scrapbook Video Productions, and they began work on a documentary.

Their film, “Discovering Dave — Spirit Captured in Clay,” is expected to be completed and released this year for selected local showings and educational television.

“We have five or six more interviews to do, and we plan to hire an actor to play Dave and get some shots of him at work, too,” Wingard said. “We’re aiming to have it finished by late summer, hopefully.”

It wasn’t just the quality of the clay vessels that made Dave special. He was also a poet who, despite being born into slavery, learned to read and write — and inscribed insightful verses on some of his jars.

His vessels, often signed and dated like the one found at the site, can be seen at the Smithsonian Institution, the Philadelphia Museum, the Museum of Early Southern Decorative Arts in North Carolina, Atlanta’s High Museum, Boston’s Museum of Fine Arts and Detroit’s African-American Museum.

The Dave jar found at the Savannah River Site, however, is unusual in that it is available for everyone to see, enjoy — even touch.

“These pots were made to be used — to keep meat, lard or butter — so they were utilitarian,” Wingard said. “Today, so many of these pots are behind glass or hidden in private collections, but our pot is still being used in a utilitarian way. People can touch it and feel it. They can even run their fingers across Dave’s name.”

Experts interviewed for the film include University of South Carolina Aiken history professor Maggi Morehouse; Edgefield potter Stephen Ferrell; Leonard Todd, the author of “The Slave Potter Dave”; Laban Hill and Bryan Collier, collaborators on the book “Dave the Potter: Artist, Poet, Slave”; and University of Illinois archaeologist George Calfas, who excavated the Pottersville site in Edgefield.

In addition to chronicling the unusual life of Dave the slave, the 45-minute documentary will feature the jar and explain how it remains in use today as an educational tool to help students understand archaeology and local history and culture.

“If you look at it, the top has been snapped off, but someone beveled it smooth again and probably kept using it even after it was broken,” Wingard said. “At some point, probably in the 1920s, it was dropped and broken into many pieces, and ended up in that trash pile.”