State-of-the art scanning electron microscopes use a beam of electrons to produce greatly magnified and incredibly detailed, almost three-dimensional, images of objects.
|Photo by Dave Pape, 2009. Creative Commons License.|
One of the principal applications of this technology in archaeology is in petrographic analysis—for example, to identify the mineralogical composition of pottery. Below is a backscattered electron image of a glaze ware pottery sherd in cross section. At this resolution, the glaze shows up as a thick white band with air bubbles and mineral inclusions.
Scanning Electron Microscope (Wikipedia) explains the technology and includes a gallery of images.