World's largest gold crystal

"The lump of gold, which weighs 217.78 grams (about 7.7 ounces), was brought to Los Alamos to confirm whether it was a single crystal of gold, or a more common multiple-crystal structure....

To determine the nugget's internal structure, Rakovan and his colleagues used two sophisticated machines: a neutron single-crystal diffraction (SCD) instrument, which determines the atomic arrangement of single crystals; and a high-pressure/preferred orientation (or HIPPO) instrument, which measures the crystal structure and the orientation of crystals in a polycrystalline material. These noninvasive techniques determined that the gold piece was, indeed, a very large and very rare single crystal of gold."