Zwischgold was used to gild sacred figures. It is not actually gold leaf, which was quite expensive, but a special double-sided foil of gold and silver where the gold can be ultra-thin because it is supported by the silver base. Other microscopy techniques had been used previously to examine zwischgold, however, they only provided a 2D cross-section of the material. In other words, it was only possible to view the surface of the cut segment, rather than looking inside the material. The scientists were also worried that cutting through it may have changed the structure of the sample. But an...