An Atlantic City church is being demolished. Its rare sandstone is saving the Smithsonian Castle.

ATLANTIC CITY — Outside the First Presbyterian Church on the corner of Pennsylvania and Pacific Avenues, Benjamin Rojas, 32, described the pride he took in demolishing this 19th-century building.

As lead foreman for SJ Hauck Construction, Rojas has been part of a planning process that’s taken a year. The Hauck team is stripping the historic but damaged former church of its exterior red sandstone layer, stone by stone, packing the stones onto pallets, and driving them to Washington.

There, they will be part of a total renovation of the original Smithsonian Institution building, known as the Castle, an 1855 building of historic and architectural significance, located in the middle of the National Mall.

It’s known for its Seneca sandstone exterior, made of stones that are no longer quarried, and from the same geological formation as the stones from Atlantic City. They are a near perfect match.

It’s an unusually noble mission in what otherwise would have been the loss of one more storied and historic building in Atlantic City.

The First Presbyterian Church, built in 1867, is the place where famed A.C. political boss Enoch “Nucky” Johnson got married, and where the legendary casino chef Sister Jean Webster ran her soup kitchen across from what was then the Trump Taj Mahal.

It never recovered from damage during Hurricane Sandy in 2012, and had been out of use and deteriorating for years. The Victory First Presbyterian Deliverance Church, the congregation most recently located in the building, attempted a rebuilding project but ultimately moved to another location in Atlantic City.

In its place will be a newly built marijuana dispensary, owned by a Maryland-based company, joining more than a dozen other dispensaries in the seaside resort.

The Castle, on the other hand, has been closed for two years while it undergoes its first renovation in 50 years. It will house an expanded visitor center with public programming when it reopens.

Rojas said preparing the stones for another chapter, rather than just a demolition heap, has been rewarding.

“It’s exciting,” he said. “You learn something new every day.”

The red sandstone on the Castle, known as Seneca sandstone from the Maryland quarry, is considered so distinctive and prized that it inspired a book.

This week, the Atlantic City church’s distinctive dark red look was slowly giving way to the gray colored stone and other building material underneath. A corner of Atlantic City, where people had come to pray, marry, and eat a freely offered hearty meal, was coming undone.

Carly Bond, the Smithsonian’s associate director of architectural history and historic preservation, said the quarry that supplied the Castle closed in 1901.

“Our material came from Maryland,” she said. “The color and quality of the stone is almost identical.”

“It’s our original building, incredibly important to our mission,” she said. “It’s Gothic revival, clad in sandstone red.”

“We’ve had to look for alternate sources,” she said. “We didn’t have enough material in hand to fully restore the outside.”

Another source for sandstone, she said, has been the original D.C. Jail, built in 1910.

Bond said a member of the design team working on the Smithsonian renovation was from Atlantic City and knew about the church.

They brought a piece of stone from the Smithsonian up to Atlantic City on a visit and compared the two.

“The color matches almost exactly,” she said.

The Hauck Construction company has posted on Facebook that the two buildings used stone from the same quarry, but Bond says the stone is actually from the same geological formation that crosses many states and once supplied multiple quarries.

“This church holds a special place in our hearts for a multitude of reasons,” Hauck, a company mostly familiar in South Jersey for its house-elevating efforts post-Sandy, posted on Facebook.

“This has been an incredible undertaking, but ensuring the stones of this building are safely removed and sent off to DC for the Smithsonian Castle is motivation enough.”

In another post, the construction company called the ongoing reclamation of the stone, in which each stone is meticulously separated by hand (and chipper hammer), “magical.”

“The Atlantic City sandstone is the only viable option to ensure the castle itself stays true to original specs for future generations,” a post read. “So much more than a simple restoration. We are literally helping preserve history, brick by brick.”

The complexity of the job was evident one day this week, as Rojas explained that crew members were being lifted in a bucket truck to carefully remove the heavy stones.

Rojas said the crews were working from the top down, using a chute to bring down the stones, before they are packed onto flatbeds for the trip to D.C. He estimates it will be another four weeks before the church has fully shed its sandstone outer coat.

Not all the stone on the Castle needs to be replaced, Bond said, and some stones from Atlantic City will be saved for the future. The Smithsonian is buying the stones from the current owner of the property, she said.

The stones are like a veneer on the building, and need to be pried off, she said.

The Castle, Bond said, is “a very important building for our history and the nation.”

“It was the Smithsonian’s only building for several decades,” she said. “Every idea for the growth of the Smithsonian first started in the Castle.”

The Atlantic City church is a similar Romanesque or Gothic style. The stones are not totally interchangeable, and need to be cut and “dressed” or carved, to fit the Castle’s decorative elements.

The reddish brown sandstone is “incredibly durable,” Bond said.

While the loss of the historic building in Atlantic City is regrettable, Bond praised the salvaging of the material.

“At least we’re able to save this material from the landfill,” she said, “and to help use it to save another historic building.”