Tuff [SPTU] - jcgomezz/Building_taxonomy GitHub Wiki

Tuff is an igneous volcanic rock made up of rock and mineral fragments that are compacted with volcanic ash. In general, the grain size of the ash is below 4 mm (above 4 mm: volcanic breccia). The colour of tuff is variable (and strongly depends on its weathering and chemical composition), but it is mostly greyish, brown, or yellow It is a low-density, high-porosity rock that is often soft and porous and can therefore be scratched by metal objects. It is a relatively soft stone and it has been widely used for masonry construction in regions where it is available (e.g. Italy, Armenia, etc.).

Tuff stone blocks, Italy (A. Benedetti)

A view of Sovana, Italy - most buildings are built using tuff masonry and the city was built on a tuff cliff (http://ilcasale1742.it/en/)

Tuff stone was used for the construction of Bourbon del Monte Palace (16th century), Sovana, Italy (www.fototoscana.it)

Tuff stone used in modern wall construction, Italy (A. Benedetti)

A wall built using dressed tuff stone exterior wythe over a rubble masonry in San Giuliano damaged in the 2002 Molise earthquake, Italy (A. Benedetti)

Tuff stone masonry in Algiers, Algeria was affected by the 2003 Boumerdes earthquake (M. Farsi)