Pyroclastic rocks

rocks composed solely or primarily of fragments derived from explosive volcanic activity

form of lava

thumb|240px|An ashlar block of peperino dating from Roman times thumb|240px|The Porta Pretoria in Albano Laziale, [[Italy. A clear example of the durability and grey surface of peperino.]] thumb|240px|A fountain Stone sculpture|sculpted from peperino, in Marino, Italy Peperino is an Italian word describing a brown or grey volcanic tuff, containing fragments of basalt and limestone, with disseminated crystals of augite, mica, magnetite, leucite, and other similar minerals. The name originally referred to the dark-colored inclusions, suggestive of peppercorns.