The shape of cavity openings tends to be ellipsoidal, elongated, and parallel to the ground in both desert and coastal settings. With the exception of inselbergs in Jordan, the major axis of elongation is about parallel to the ground. Tafoni openings are ~40% wider than higher (roughly perpendicular to the ground). Smaller, millimeter- to centimeter-scale cavities are reported on more often in temperate and tropical areas, like in the intertidal zone or at near shore coastal environments. Centimeter- to meter-scale tafoni may be more abundant in arid than wetter climates. Coastal tafoni may also be deeper than desert tafoni relative to the size of the opening; this observation may be an artifact of the accelerated nature of coastal rather than desert tafoni growth.

The following summarizes tafoni morphometrics for clastic rocks in different environmental settings.

Note that width is the horizontal diameter of cavity opening parallel to the ground and height is vertical diameter of cavity opening from the ground toward the sky. Depth is the maximum distance from the plane of the cavity opening to the back of the cavity towards the rock outcrop.