It's a single gold crystal that "seemed almost too perfect and too big to be real," per a press release about it. Roughly the size of a golf ball, it was found in a Venezuela river decades ago, reports KRQE, and worth an estimated $1.5 million—so long as it was indeed a single-crystal piece, as opposed to the more typical multiple-crystal variety. The 217.78-gram (roughly 7.7-ounce) nugget was one of four that the owner provided to geologist John Rakovan in a bid to determine its authenticity. But peering into the structure of a piece this big is something that the Miami University professor explains had never been done before.
Rakovan took the pieces to Los Alamos National Laboratory, whose Lujan Neutron Scattering Center offered him the chance to employ neutron diffractometry—the use of neutrons allowed him to penetrate several centimeters into the stone without damaging it, something X-rays and electrons could not. What he and his collaborators found: Three of the four pieces were indeed single-crystal, including the large one in question. The press release notes that further analysis of the findings "will also provide an understanding of how the rare pieces may have formed before they were slightly deformed while being washed down in ancient stream sediments." A scientific report is forthcoming. (More wild gold news: Scientists have found gold in eucalyptus trees.)