Diagram showing how atoms of copper are stacked within a cube. The black dots represent the cores of the atoms; they are located on each corner of the cube and at the center of each face. This crystalline structure is called face-centered-cubic (FCC). After Scott, David A. 1991. Metallography and Microstructure of Ancient and Historic Metals. Marina del Rey, CA: Getty Conservation Institute in association with Archetype Books., 1, fig. 2.