Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
  
Basalt is a common extrusive igneous rock formed by the rapid cooling of basaltic lava exposed at or very near the surface of Earth
  
History
  
  
Origin
Egypt
  
Egypt
  
Discoverer
Unknown
  
Georgius Agricola
  
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
  
From Late Latin Basaltes (variant of basanites ), very hard stone, which was imported from Ancient Greek Basanites
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Plutonic
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Porphyritic
  
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
  
Color
Black, Brown, Colourless, Green, Grey, Red, Rust, White
  
Black, Brown, Light to Dark Grey
  
Maintenance
Less
  
More
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
No
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
Yes
  
Wind Resistant
No
  
No
  
Acid Resistant
Yes
  
Yes
  
Appearance
Dull
  
Dull and Soft
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Interior Decoration
  
Floor Tiles, Homes, Hotels, Kitchens
  
Exterior Uses
Garden Decoration, Paving Stone
  
As Building Stone, Paving Stone, Garden Decoration, Office Buildings
  
Other Architectural Uses
Curbing
  
Curbing, Whetstones
  
Industry
  
  
Construction Industry
Construction Aggregate
  
Arrowheads, As Dimension Stone, Cobblestones, Cutting Tool, Rail Track Ballast, Roadstone
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture
  
Artifacts, Monuments
  
Other Uses
  
  
Commercial Uses
Creating Artwork, Gemstone, Jewelry
  
An Oil and Gas Reservoir, Commemorative Tablets, Creating Artwork, Used in aquariums
  
Types
Rhomb Porphyry
  
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
  
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
  
Has High structural resistance against erosion and climate, Very fine grained rock
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Easter Island in the Polynesian Triangle, Pacific Ocean, Gateway of India in Mumbai, India, Gol Gumbaz in Karnataka, India
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Not Used
  
Used
  
Petroglyphs
Not Used
  
Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
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.
  
Basalt forms when lava reaches the Earth's surface near an active volcano. The temperature of lava is between 1100 to 1250° C when it gets to the surface.
  
Composition
  
  
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
  
Olivine, Plagioclase, Pyroxene
  
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
  
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Contact Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Not Registered
  
Biological Weathering
  
Erosion
Yes
  
No
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
  
Not Available
  
Physical Properties
  
  
Hardness
6-7
  
6
  
Grain Size
Fine Grained
  
Fine Grained
  
Fracture
Irregular
  
Conchoidal
  
Streak
White
  
White to Grey
  
Porosity
Less Porous
  
Less Porous
  
Luster
Dull
  
Not Available
  
Compressive Strength
Not Available
  
37.40 N/mm
2
  
28
Cleavage
Imperfect
  
Not Available
  
Toughness
1.7
  
2.3
  
Specific Gravity
2.5-4
  
2.8-3
  
Transparency
Translucent to Opaque
  
Opaque
  
Density
2.5-2.52 g/cm3
  
2.9-3.1 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
Not Available
  
0.84 kJ/Kg K
  
15
Resistance
Heat Resistant, Impact Resistant
  
Heat Resistant, Pressure Resistant, Wear Resistant
  
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
  
Iceland
  
Others
Greenland
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Cuba, Jamaica, USA
  
Canada, USA
  
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Western Australia
  
Not Yet Found