pit rock

Pit rock is a tile in the Factorio system categorized as a decoration; it is a decorative ground tile used to change the visual appearance of terrain without affecting gameplay mechanics like movement cost or pollution absorption. As a cosmetic surface option, Pit rock is applied to the map to create rocky pit-style ground visuals for base building and map design, and it interacts with the game's tile placement and landscaping systems but does not provide production, resource, or defensive functions.