The microscopic examination of metal artifacts with the aim of studying their manufacturing techniques rather than their composition. A sample is taken from the artifact, preferably a cross-sectional slice, and it is highly polished. The surface is then etched in order to dissolve some of the metal, leaving visible its internal structure for examination under a metallurgical microscope. This uses reflected light which emphasizes the uneven surfaces revealed by the etching process and caused by such features as the boundaries between grains of metal. The size and shape of the grains or dendrites in a metal (crystalline structure), as well as other details of microstructure, can yield information on casting methods or post-casting working. The technique can be used on both ferrous and non-ferrous metals.