In geology, boxwork is defined as a honeycomb-like structure that can form in some fractured or jointed sedimentary rocks. If the fractures in the host rock are mineralized, they can become more resistant to weathering than the surrounding rock, and subsequent erosion can produce boxwork structures. In mining geology, boxwork is a set of (typically) quartz-lined cavities, retaining the shape of the dissolved ore minerals, in gossans. In classical geology or mineralogy these mineral casts would not be called boxwork, but would instead be called pseudomorphs, or epimorphs. In cave geology, boxwork is an uncommon type of mineral structure, or speleogen (similar to a speleothem, but formed by erosion rather than accretion), occasionally found in caves and erosive environments.