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
Porphyritic
Color
Black, Brown, Green, Grey, Red, Rust, White
Maintenance
Less
Durability
Durable
Water Resistant
✔
✘
81% - Igneous Rocks Rocks
Scratch Resistant
✔
✘
86% - Igneous Rocks Rocks have it !
Stain Resistant
✔
✘
66% - Igneous Rocks Rocks have it !
Wind Resistant
✔
✘
49% - Igneous Rocks Rocks
Acid Resistant
✔
✘
48% - Igneous Rocks Rocks have it !
Appearance
Dull
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
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
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
✔
✘
97% - Igneous Rocks Rocks have it !
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
99% - Igneous Rocks Rocks have it !
Types of Weathering
Biological Weathering, Chemical Weathering
Erosion
✔
✘
92% - Igneous Rocks Rocks have it !
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Physical Properties
Hardness
6-7
1
7
👆🏻
Grain Size
Fine Grained
Fracture
Irregular
Streak
White
Porosity
Less Porous
Luster
Dull
Compressive Strength
150.00 N/mm2
Rank: 22 (Overall)
0.15
450
👆🏻
Cleavage
-
Toughness
1.7
Specific Gravity
2.5-4
0
8.4
👆🏻
Transparency
Translucent to Opaque
Density
2.5-2.52 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.71 kJ/Kg K
Rank: 23 (Overall)
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
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