Golden Buckyballs are clusters of gold atoms, and are only about 6 angstroms across, 6 millionths the diameter of a human hair. The ultimate gift for that special someone? Scientists at the Pacific Northwest National Laboratory in Richland and at the University of Nebraska report in today's Proceedings of the National Academy of Sciences that they have discovered hollow molecular structures made of pure gold -- golden buckyballs. Carbon buckyballs, hollow spheres made of 60 carbon atoms and named for the geodesic dome designed by Buckminster Fuller, were discovered in the early 1980s. Originally known as buckminsterfullerenes (today, technically, just as fullerenes), buckyballs became the third known natural form of pure carbon after diamond and graphite. In today's report, Lai-Sheng Wang, a national lab scientist and professor of physics at Washington State University, said his team appears to have created the first metallic version of the buckyball. Co-authors are Xiao Cheng Zeng and chemist Satya Bulusu, both of the University of Nebraska, and Xi Li, a WSU physics graduate student. "We weren't specifically looking for this," Wang said. "We were just interested in gold nanoparticles." Elemental gold has a number of useful properties. In large quantities, such as for a ring or an earring, gold reacts with little and retains its expensive luster. But in very tiny quantities, at the scale of individual atoms (or "nanoscale"), gold's character changes dramatically. "It becomes highly reactive, a very good catalyst," Wang said. He and his team continued to work with gold at the nanoscale. Years ago, Wang's team created a pyramid made of 20 gold atoms. Nobody thought anything besides carbon could form a buckyball, he said. But before coming to Richland, Wang had worked with Richard Smalley, the Rice University scientist who led the team that discovered the original buckyball. Over the past few years, Wang joined others searching for evidence of this happening in metals. The carbon buckyball naturally forms into a nanosphere of 60 atoms. Though they weren't discovered until recently, buckyballs are produced naturally in common chemical reactions such as soot from a burning candle. Yet the discovery of buckyballs paved the way for much of today's nanotechnology -- the art and science of working at the atomic level. In order to look for golden buckyballs, Wang and his team used a laser to vaporize gold. The zapped gold atoms condensed inside a vacuum and formed clusters varying in size from two to 100 atoms, Wang explained. That was the easy part, he said. "The rest of it was detective work," Wang said. It took them years of analyzing the spectroscopic signatures of these clusters to determine if any might be hollow, he said. What they eventually were able to discern is that only clusters of 16 to 18 atoms form hollow cages. Fewer atoms, Wang said, and you get flat gold. More than 18 atoms, he said, and it's just solid gold. So what good are these golden buckyballs? How will they be put to use? "You can put another atom in the center," Wang said. Depending upon the kind of atom put at the center of the cage, he said, you could create a material with novel chemical, magnetic or even optical properties. "We intend to try that."