Tuffite

a volcanogenic sedimentary rock consisting of volcanogenic material ejected during a volcanic eruption (for example, scoria, ash, pumice, and rock fragments) and sedimentary material mixed with the volcanogenic material. Tuffite may contain rounded fragments of intrusive rocks and also quartz, feldspar, biotite, and organic remains. The cement may be carbonate or argillaceous. Tuffite is used as a building material. (See alsoVOLCANOGENIC SEDIMENTARY ROCK.)