Definition
Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Origin
North America
Egypt
Discoverer
Theodor von Gümbel
Unknown
Etymology
From Andes mountains, where it is found in abundance
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
Aphanitic to Porphyritic
Porphyritic
Color
Bluish - Grey, Grey, Pink, Yellow
Black, Brown, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Dull
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens
Decorative Aggregates, Interior Decoration
Exterior Uses
Office Buildings, Roof Tiles
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cobblestones, Construction Aggregate, for Road Aggregate
Construction Aggregate
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone, Jewelry
Types
Icelandite
Rhomb Porphyry
Features
Generally rough to touch, High silica content, Is one of the oldest rock
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Famous Monuments
Middle of the Earth in Ecuador
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Formation
Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.
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
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
Silicon 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, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Very fine-grained
Fine Grained
Fracture
Uneven
Irregular
Porosity
Less Porous
Less Porous
Specific Gravity
2.5-2.8
2.5-4
Transparency
Opaque
Translucent to Opaque
Density
2.11-2.36 g/cm3
2.5-2.52 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
India, Indonesia, Japan, Nepal, South Korea
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania
Egypt, Ethiopia, Ghana, South Africa
Europe
Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Deposits in Western Continents
North America
Mexico, USA
Canada, Cuba, Jamaica, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
New South Wales, New Zealand, Western Australia
Andesite 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. Andesite vs Porphyry characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Andesite and Properties of Porphyry. Learn more about Andesite vs Porphyry in the next section. The interior uses of Andesite include Decorative aggregates, Floor tiles, Homes, Interior decoration and Kitchens whereas the interior uses of Porphyry include Decorative aggregates and Interior decoration. Due to some exceptional properties of Andesite and Porphyry, they have various applications in construction industry. The uses of Andesite in construction industry include Cobblestones, Construction aggregate, For road aggregate and that of Porphyry include Construction aggregate.
More about Andesite and Porphyry
Here you can know more about Andesite and Porphyry. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Andesite and Porphyry consists of mineral content and compound content. The mineral content of Andesite includes Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon and mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica. You can also check out the list of all Igneous Rocks. When we have to compare Andesite vs Porphyry, the texture, color and appearance plays an important role in determining the type of rock. Andesite is available in bluish - grey, grey, pink, yellow colors whereas, Porphyry is available in black, brown, green, grey, red, rust, white colors. Appearance of Andesite is Dull and Soft and that of Porphyry is Dull. Properties of rock is another aspect for Andesite vs Porphyry. The hardness of Andesite is 7 and that of Porphyry is 6-7. The types of Andesite are Icelandite 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 Andesite and Porphyry is white. The specific heat capacity of Andesite is 2.39 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.Andesite is heat resistant, pressure resistant, wear resistant whereas Porphyry is heat resistant, impact resistant.