Types of Chert and Phonolite
Some rocks according to their use or texture are classified into different types. Know more about Chert Texture and Phonolite Texture. Types of Chert are Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter whereas the types of Phonolite are Kenyte.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. Chert was not used to create pictographs whereas Phonolite 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. Chert was not used to create petroglyphs whereas Phonolite was used to create petroglyphs.