Types of Porphyry and Tuff
Some rocks according to their use or texture are classified into different types. Know more about Porphyry Texture and Tuff Texture. Types of Porphyry are Rhomb Porphyry whereas the types of Tuff are Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite..During historic times, some rocks depending on their hardness were used to create Pictographs and Petroglyphs. Rocks which are hard were generally not used. Pictographs are paintings or drawings that have been placed or created on the surface of rock. Porphyry was not used to create pictographs whereas Tuff is used to create pictographs. Petroglyph is an image which is carved into a rock. These are images created by removing part of a rock surface by incising, picking, carving or abrading, as a form of rock art. Porphyry was not used to create petroglyphs whereas Tuff was used to create petroglyphs.