A geofact (a portmanteau of geology and artifact) is a natural stone formation that is difficult to distinguish from a man-made artifact. Geofacts could be fluvially reworked and be misinterpreted as an artifact, especially when compared to Paleolithic artifacts.
Possible examples include several purported prominent ancient artifacts, such as the Venus of Berekhat Ram and the Venus of Tan-Tan. These are thought by many in the archaeological community to be geofacts. A site which shows an abundance of what are likely geofacts is the Gulf of Cambay.
Geofacts can be distinguished from lithic debitage, through experiments and comparisons. Separating geofacts from artifacts is a challenge that archaeologists can face while excavating a site.