All images Larrabee State Park, WA Barbara De Pirro
Honeycomb weathering, also known as fretting, cavernous weathering, alveoli/alveolar weathering, stone lattice, stone lace or miniaturetafoni weathering is a form of salt weathering common on coastal and semi-arid granites, sandstones and limestones.
For honeycomb weathering to occur a source of salt is needed because the basic mechanism for this kind of weathering is salt heaving. Salt is deposited on the surface of the rock by saltwater spray or by wind. Moisture must be present to allow for the salt to settle on the rocks so that as the salt solution evaporates the salt begins to crystallize within the pore-spaces of the rock. Permeable rock is also needed so that there are pore-spaces for the salt to crystallize within. These salt crystals pry apart the mineral grains, leaving them vulnerable to other forms of weathering. It takes prolonged periods for this weathering to become visible, as the rock goes through cycles of wetting and drying.
