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Porphyry and Gabbro


Gabbro and Porphyry


Definition

Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix   
Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt   

History
  
  

Origin
Egypt   
Germany   

Discoverer
Unknown   
Christian Leopold von Buch   

Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites   
From Latin glaber bare, smooth, bald   

Class
Igneous Rocks   
Igneous Rocks   

Sub-Class
Durable Rock, Hard Rock   
Durable Rock, Hard Rock   

Family
  
  

Group
Plutonic   
Plutonic   

Other Categories
Fine Grained Rock, Opaque Rock   
Coarse Grained Rock, Opaque Rock   

Texture

Texture
Porphyritic   
Phaneritic   

Color
Black, Brown, Colourless, Green, Grey, Red, Rust, White   
Dark Grey to Black   

Maintenance
Less   
Less   

Durability
Durable   
Durable   

Water Resistant
No   
Yes   

Scratch Resistant
Yes   
Yes   

Stain Resistant
Yes   
Yes   

Wind Resistant
No   
Yes   

Acid Resistant
Yes   
Yes   

Appearance
Dull   
Veined and Shiny   

Uses

Architecture
  
  

Interior Uses
Decorative Aggregates, Interior Decoration   
Countertops, Decorative Aggregates, Homes, Interior Decoration   

Exterior Uses
Garden Decoration, Paving Stone   
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone   

Other Architectural Uses
Curbing   
Curbing   

Industry
  
  

Construction Industry
Construction Aggregate   
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts, Monuments, Sculpture   
Artifacts, Monuments, Sculpture   

Other Uses
  
  

Commercial Uses
Creating Artwork, Gemstone, Jewelry   
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones   

Types

Types
Rhomb Porphyry   
Not Available   

Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny   
Smooth to touch   

Archaeological Significance
  
  

Monuments
Used   
Used   

Famous Monuments
Data Not Available   
Data Not Available   

Sculpture
Used   
Used   

Famous Sculptures
Data Not Available   
Data Not Available   

Pictographs
Not Used   
Not Used   

Petroglyphs
Not Used   
Not Used   

Figurines
Used   
Used   

Fossils
Absent   
Absent   

Formation

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.   
Gabbro, a mafic rock, forms due to cooling and crystallization of magma underneath Earth's surface.   

Composition
  
  

Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica   
Augite, Olivine, Plagioclase, Pyroxene   

Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide   
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide   

Transformation
  
  

Metamorphism
Yes   
Yes   

Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism   
Impact Metamorphism   

Weathering
Yes   
Yes   

Types of Weathering
Biological Weathering, Chemical Weathering, Not Registered   
Chemical Weathering   

Erosion
Yes   
Yes   

Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion   
Coastal Erosion   

Properties

Physical Properties
  
  

Hardness
6-7   
7   

Grain Size
Fine Grained   
Coarse Grained   

Fracture
Irregular   
Conchoidal   

Streak
White   
Black   

Porosity
Less Porous   
Highly Porous   

Luster
Dull   
Not Available   

Compressive Strength
Not Available   
225.00 N/mm2   
7

Cleavage
Imperfect   
Not Available   

Toughness
1.7   
1.6   

Specific Gravity
2.5-4   
2.86-2.87   

Transparency
Translucent to Opaque   
Opaque   

Density
2.5-2.52 g/cm3   
2.7-3.3 g/cm3   

Thermal Properties
  
  

Resistance
Heat Resistant, Impact Resistant   
Impact Resistant, Pressure Resistant, Wear Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam   
India, Russia   

Africa
Egypt, Ethiopia, Ghana, South Africa   
South Africa   

Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland   
Germany, Greece, Italy, Scotland, Turkey   

Others
Greenland   
Greenland   

Deposits in Western Continents
  
  

North America
Canada, Cuba, Jamaica, USA   
Canada, USA   

South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay   
Brazil, Colombia, Venezuela   

Deposits in Oceania Continent
  
  

Australia
New South Wales, New Zealand, Western Australia   
New Zealand, Queensland   

Summary >>
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All about Porphyry and Gabbro Properties

Know all about Porphyry and Gabbro properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Gabbro belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Gabbro is Phaneritic. Porphyry appears Dull and Gabbro appears Veined and Shiny. The luster of Porphyry is dull while that of Gabbro is not available. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors whereas Gabbro is available in dark grey to black colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Gabbro are cemetery markers, commemorative tablets, laboratory bench tops, jewelry, sea defence, tombstones.

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