Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Discoverer
Unknown
Unknown
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Porphyritic
Color
Black, Brown, Colourless, Green, Grey, Red, Rust, White
Black, Brown, Colourless, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Construction Aggregate
Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Creating Artwork, Gemstone, Jewelry
Types
Rhomb Porphyry
Rhomb Porphyry
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Formation
Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.
Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Not Registered
Biological Weathering, Chemical Weathering, Not Registered
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Irregular
Irregular
Porosity
Less Porous
Less Porous
Cleavage
Imperfect
Imperfect
Specific Gravity
2.5-4
2.5-4
Transparency
Translucent to Opaque
Translucent to Opaque
Density
2.5-2.52 g/cm3
2.5-2.52 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
Egypt, Ethiopia, Ghana, South Africa
Egypt, Ethiopia, Ghana, South Africa
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Others
Greenland
Greenland
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
Canada, Cuba, Jamaica, USA
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
New South Wales, New Zealand, Western Australia