Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
It is a metamorphic magnesium rich rock because it is composed of the mineral talc
Discoverer
Unknown
Unknown
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From 17th century, because of its greasy feel and use like a soap
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Group
Plutonic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Polished
Color
Black, Brown, Colourless, Green, Grey, Red, Rust, White
Black, Black to Grey, Green, Grey
Durability
Durable
Durable
Appearance
Dull
Dull, Banded and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Bathrooms, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Construction Aggregate
Manufacture of Magnesium and Dolomite Refractories
Medical Industry
Not Yet Used
Taken as a Supplement for Calcium or Magnesium
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Jewellery, Monuments, Sculpture
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)
Types
Rhomb Porphyry
Not Available
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Host Rock for Lead
Archaeological Significance
Famous Monuments
Data Not Available
Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
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.
Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
CaO, Mg, MgO
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
Not Applicable
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Not Applicable
Grain Size
Fine Grained
Fine Grained
Fracture
Irregular
Conchoidal
Porosity
Less Porous
Less Porous
Compressive Strength
Not Available
Cleavage
Imperfect
Perfect
Specific Gravity
2.5-4
2.86
Transparency
Translucent to Opaque
Opaque
Density
2.5-2.52 g/cm3
2.8-2.9 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand
Africa
Egypt, Ethiopia, Ghana, South Africa
Egypt, Ethiopia, Ghana, South Africa, Western Africa
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
Canada, USA
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Colombia
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
Central Australia, New Zealand, Queensland
All about Porphyry and Soapstone Properties
Know all about Porphyry and Soapstone properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry belongs to Igneous Rocks while Soapstone belongs to Metamorphic Rocks.Texture of Porphyry is Porphyritic whereas that of Soapstone is Polished. Porphyry appears Dull and Soapstone appears Dull, Banded and Foilated. The luster of Porphyry is dull while that of Soapstone is greasy. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors whereas Soapstone is available in black, black to grey, green, grey colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Soapstone are cemetery markers, creating artwork, gemstone, jewelry, manufacture of soap, solvents, dyes, plastics and fibres, production of lime, source of magnesia (mgo).