Tafoni

in the scientific literature, tafoni are commonly defined as small (less than 1 cm (0.39 in)) to large (greater than 1 meter (3.3 ft)) cavity features that develop in either natural or manmade, vertical to steeply sloping, exposures of granular rock (i.e., granite, sandstone) with smooth concave walls, and often round rims and openings.

They typically develop in siliceous, either coarse-grained (sandstone) or coarsely crystalline (granite), rock types.

They can be found in all climate types, but are most prolific in salt-rich environments, such as deserts and coastal zones.

The common factors in the environments in which they are found are high salt concentrations and frequent or occasional desiccating conditions.

Starting in the 1970s, most workers have advocated salt weathering as the primary explanation for the formation of tafoni.