Definition
Greenschist is a metamorphic rock that is formed under lowest temperatures and pressures and is usually produced by regional metamorphism
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 minerals such as chlorite, serpentine, and epidote, and platy minerals such as muscovite and platy serpentine which are green in color
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Foliated, Platy
Porphyritic
Color
Dark Greenish - Grey, Green
Black, Brown, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Layered and Shiny
Dull
Interior Uses
Bathrooms, Countertops, Decorative Aggregates, Entryways, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Cutting Tool, for Road Aggregate, Roadstone
Construction Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Blackboards, Manufacture of tools, Writing Slates
Creating Artwork, Gemstone, Jewelry
Types
Metamorphic rock
Rhomb Porphyry
Features
Easily splits into thin plates, Smooth to touch
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Formation
Greenschist is medium grade metamorphic rock, formed by the metamorphosis of mudstone or shale, or some types of igneous rock, when it is subjected to higher temperatures and pressures.
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
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Serpentine, Sillimanite, Staurolite, Talc
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
CaO, Carbon Dioxide, MgO
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
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Irregular
Porosity
Highly Porous
Less Porous
Specific Gravity
2.5-2.9
2.5-4
Transparency
Opaque
Translucent to Opaque
Density
2.8-2.9 g/cm3
2.5-2.52 g/cm3
Resistance
Impact Resistant, Pressure Resistant, Water Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Egypt, Ethiopia, Ghana, South Africa
Europe
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, Cuba, Jamaica, USA
South America
Brazil, Colombia, Guyana
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland
New South Wales, New Zealand, Western Australia
Greenschist vs Porphyry Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Greenschist vs Porphyry characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Greenschist and Properties of Porphyry. Learn more about Greenschist vs Porphyry in the next section. The interior uses of Greenschist include Bathrooms, Countertops, Decorative aggregates, Entryways, Homes and Interior decoration whereas the interior uses of Porphyry include Decorative aggregates and Interior decoration. Due to some exceptional properties of Greenschist and Porphyry, they have various applications in construction industry. The uses of Greenschist in construction industry include As dimension stone, Building houses or walls, Cement manufacture, Cutting tool, For road aggregate, Roadstone and that of Porphyry include Construction aggregate.
More about Greenschist and Porphyry
Here you can know more about Greenschist and Porphyry. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Greenschist and Porphyry consists of mineral content and compound content. The mineral content of Greenschist includes Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Serpentine, Sillimanite, Staurolite, Talc and mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica. You can also check out the list of all Metamorphic Rocks. When we have to compare Greenschist vs Porphyry, the texture, color and appearance plays an important role in determining the type of rock. Greenschist is available in dark greenish - grey, green colors whereas, Porphyry is available in black, brown, green, grey, red, rust, white colors. Appearance of Greenschist is Layered and Shiny and that of Porphyry is Dull. Properties of rock is another aspect for Greenschist vs Porphyry. The hardness of Greenschist is 3.5-4 and that of Porphyry is 6-7. The types of Greenschist are Metamorphic rock whereas types of Porphyry are Rhomb Porphyry. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Greenschist and Porphyry is white. The specific heat capacity of Greenschist is 0.84 kJ/Kg K and that of Porphyry is 0.71 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Greenschist is impact resistant, pressure resistant, water resistant whereas Porphyry is heat resistant, impact resistant.