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Porphyry Rock



Definition

Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix

History

Origin
Egypt

Discoverer
Unknown

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

Class
Igneous Rocks

Sub-Class
Durable Rock, Hard Rock

Family

Group
Plutonic

Other Categories
Fine Grained Rock, Opaque Rock

Texture

Texture
Porphyritic

Color
Black, Brown, Green, Grey, Red, Rust, White

Maintenance
Less

Durability
Durable

Water Resistant
No

Scratch Resistant
Yes

Stain Resistant
Yes

Wind Resistant
No

Acid Resistant
Yes

Appearance
Dull

Uses

Architecture

Interior Uses
Decorative Aggregates, Interior Decoration

Exterior Uses
Garden Decoration, Paving Stone

Other Architectural Uses
Curbing

Industry

Construction Industry
Construction Aggregate

Medical Industry
-

Antiquity Uses
Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses
Creating Artwork, Gemstone, Jewelry

Types

Types
Rhomb Porphyry

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

Archaeological Significance

Monuments
-

Famous Monuments
-

Sculpture
-

Famous Sculptures
-

Pictographs
-

Petroglyphs
-

Figurines
-

Fossils
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.

Composition

Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica

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

Transformation

Metamorphism
Yes

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

Weathering
Yes

Types of Weathering
Biological Weathering, Chemical Weathering

Erosion
Yes

Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness
6-7

Grain Size
Fine Grained

Fracture
Irregular

Streak
White

Porosity
Less Porous

Luster
Dull

Compressive Strength
150.00 N/mm2 22

Cleavage
-

Toughness
1.7

Specific Gravity
2.5-4

Transparency
Translucent to Opaque

Density
2.5-2.52 g/cm3

Thermal Properties

Specific Heat Capacity
0.71 kJ/Kg K 23

Resistance
Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

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

Africa
Egypt, Ethiopia, Ghana, South Africa

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

Others
Greenland

Deposits in Western Continents

North America
Canada, Cuba, Jamaica, USA

South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay

Deposits in Oceania Continent

Australia
New South Wales, New Zealand, Western Australia

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Igneous Rocks

Information about Porphyry

Rocks are naturally occurring solids which are composed of minerals & have been used by humans since ages. From Stone Age, rocks are used for various purposes. Also, the metals and minerals found in rock play an important role in our life. Get to know all the Porphyry Uses. We have provided you with all information about Porphyry rock here. Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix. Porphyry is available in black, brown, green, grey, red, rust, white colors. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Porphyry is white. Get to know more about Porphyry rock and characteristics of Porphyry rock in the next sections.

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