Shale and Porphyry Types and Facts
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Rhomb Porphyry
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Famous Monuments
Jantar Mantar in India
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Types of Shale and Porphyry
Some rocks according to their use or texture are classified into different types. Know more about Shale Texture and Porphyry Texture. Types of Shale are Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale whereas the types of Porphyry are Rhomb Porphyry.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. Shale was used to create pictographs whereas Porphyry is not 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. Shale was used to create petroglyphs whereas Porphyry was not used to create petroglyphs.