Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Cataclasite is a type of cataclastic rock that is formed by fracturing and comminution during faulting. It is normally cohesive and non-foliated, consisting of angular clasts in a finer-grained matrix
Origin
Egypt
Swiss Alps, Europe
Discoverer
Unknown
Michael Tellinger
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From the Italian word cataclasi
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Clastic
Color
Black, Brown, Green, Grey, Red, Rust, White
Brown, Green, White, Yellow
Durability
Durable
Durable
Appearance
Dull
Dull and Banded
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Construction Aggregate
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Commemorative Tablets, Creating Artwork
Types
Rhomb Porphyry
Protocataclasite, Mesocataclasite, Ultracataclasite and Foliated cataclasite
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Easily splits into thin plates, Is one of the oldest rock
Archaeological Significance
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.
Cataclasiste rocks mainly form by pressure deep under the Earth's surface, from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Albite, Apatite, Augite, Biotite, Calcite, Enstatite, Epidote, Feldspar, Micas, Muscovite or Illite, Pyroxene, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
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Types of Weathering
Biological Weathering, Chemical Weathering
Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Coastal Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Porosity
Less Porous
Less Porous
Specific Gravity
2.5-4
2.1
Transparency
Translucent to Opaque
Translucent to Opaque
Density
2.5-2.52 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
China, India, Russia, Saudi Arabia, South Korea
Africa
Egypt, Ethiopia, Ghana, South Africa
Egypt, Ethiopia, Kenya, Madagascar, Morocco, South Africa
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
England, Finland, France, Spain, United Kingdom
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
Canada, USA
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Argentina, Colombia
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
Central Australia, Western Australia