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What is Porphyry?



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

Summary >>
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Igneous Rocks

Learn more about Properties of Porphyry

What is Porphyry? In this section, we will learn more about properties of Porphyry i.e. physical and thermal properties. Physical properties of Porphyry include Color, Streak, Hardness, Structure, Cleavage, Fracture, Luster, Specific Gravity etc. The strength of Porphyry is 150.00 N/mm2. Streak of Porphyry is white while its cleavage is . Luster of Porphyry is dull and its fracture is irregular. Porphyry is translucent to opaque in nature. Know all about Porphyry, What is Porphyry, its composition, features, facts and reserves in next sections.

Know about Composition of Porphyry

What is Porphyry composed of? Get to know about composition of Porphyry here. Porphyry definition gives information about the Formation of Porphyry and its composition.The composition of Porphyry can be further divided into mineral and compound content. The mineral content of Porphyry rock includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica and The compound content of Porphyry rock includes Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide. Almost all rocks undergo transformation process. Know all about Porphyry rock in next section.

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