You've seen it all around West Campus--from the Chapel to Cameron Indoor Stadium, on the new tennis stadium and soon you will see it on the tower of the new West-Edens Link.
It is Duke stone, mined locally in a six-acre Hillsborough quarry inside Duke Forest, and used all across the University's campus to cover buildings.
Judith White, assistant vice president and director of the residential program review, said the exterior of the WEL's tower will be covered entirely in what has become known as "Duke stone."
"At our current quarry, we found another vein of the black [stone], which has been missing in some of the combinations of Duke stone we've used recently," White said.
According to a 1990 article by William King, former University archivist, University benefactor James B. Duke had inspected stone imported from places as far as Massachusetts, but quietly sought stone closer to the University.
"Because it provided the type of stone that Mr. Duke wanted for the new campus, the original quarry area was purchased there in the 1920s and '30s. Apparently Duke first had a deed to the stone conveyed about 1925," said Judson Edeburn, resource manager of Duke Forest.
Officials found that stone at a local farm in Hillsborough, which Duke quickly bought--saving $2 million in costs for original construction.
Currently, the stone costs about $120 per ton, significantly lower than it would be from an outside source.
Joe Jackson, grounds and sanitation manager for the Facilities Management Department, said a majority of current projects will have some percentage of stone, but that because of cost, most buildings use brick as well, finding ways of making things "look like Duke" without making them cost like Duke.
But White said brick is sometimes difficult to make look exactly like stone. "Brick doesn't take that much variation," she said. "It changes color in the way we see it, sun, shadow. Should it look like stone in sunlight? Should it look like stone when it's wet?"
Daniel Richter, professor of environmental studies, said the stone, Carolina slate, covers extensive areas from Virginia to eastern Alabama.
Richter said the volcanic rock has a fine grain because it has been highly metamorphosed.
"Geologists don't really know the origin, whether it's from volcanic ashfall, which happens nearby any big volcanic activity, or more from liquid lava," he said.
Richter explained that as the iron and iron oxides in the stone are exposed to weathering, those elements rust, and the rock takes on a variety of colors--from red to orange to blue.
Duke stone has 17 different shades of color within seven primary colors.
White said no two buildings had the exact same combinations of Duke stone. For instance, the WEL tower will use more gray and black stone than the Wilson Recreation Center, which used more brown.
Richter said that when the Levine Science Research Center--which did not use Duke stone--was being built, he had heard architects express concern over how much blue stone would be left in the quarry. Most of the buildings constructed in the 1970s and 1980s, such as the Bryan Center, used relatively little of the Duke stone.
Jackson said that although the quarry may produce different colors at different times, Duke stone should continue to be part of the construction picture in the future.
"We think we have, from the last study we had conducted, we've got enough stone for many years to come," Jackson said.
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