Definition
An iron rich extrusive rock found as a member of the alkali basalt magma series
Anorthosite is a granular igneous rock composed largely of labradorite or plagioclase
History
Origin
Isle of Mull, Scotland
-
Discoverer
Ben More
Unknown
Etymology
From the name of discoverer, Ben More
From French anorthose plagioclase + -ite1
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Trachytic, Vesicular
Foliated, Glassy
Color
Black, Brown, Light to Dark Grey
Black, Bluish - Grey, Brown, Green, Grey, Light Greenish Grey, Pink, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Rough and Dull
Layered, Banded, Veined and Shiny
Architecture
Interior Uses
Floor Tiles, Homes, Hotels, Kitchens
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
As Dimension Stone, Cement Manufacture, for Road Aggregate
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture, Small Figurines
Other Uses
Commercial Uses
Commemorative Tablets, Creating Artwork, Curling
Creating Artwork, Curling
Types
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB) and Tholeiitic Basalt
Proterozoic Anorthosite and Archean Anorthosite
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Benmoreite is a type of Igneous rock which is formed through the cooling and solidification of lava or magma. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal mafic component.
Composition
Mineral Content
Alkali feldspar, Biotite, Olivine, Plagioclase, Pyroxene, Sodic plagioclase
Amphibole, Clinopyroxene, Ilmenite, Magnetite, Olivine, Orthopyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, CaO, Chromium(III) Oxide, MgO, Sulfur Trioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Cataclastic Metamorphism, Contact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Wind Erosion
Physical Properties
Hardness
65-6
1
7
👆🏻
Grain Size
Fine Grained
Coarse Grained
Fracture
Conchoidal
Irregular
Streak
Black
White
Porosity
Less Porous
Less Porous
Luster
Earthy
Pearly to Subvitreous
Compressive Strength
37.40 N/mm2180.00 N/mm2
0.15
450
👆🏻
Cleavage
Perfect
-
Toughness
2.3
-
Specific Gravity
2.8-32.62-2.82
0
8.4
👆🏻
Transparency
Opaque
Translucent
Density
2.9-3.1 g/cm32.7-4 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K0.84 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
-
Africa
South Africa
-
Europe
Iceland
Bulgaria, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Malta, Poland, Portugal, Romania, Slovenia, Spain, Sweden, The Czech Republic
Others
-
-
Deposits in Western Continents
North America
Canada, USA
Canada
South America
Brazil
Bolivia, Colombia
Deposits in Oceania Continent
Australia
-
Central Australia, South Australia, Western Australia