Anorthosite and Skarn
Definition
Definition
Anorthosite is a granular igneous rock composed largely of labradorite or plagioclase
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
History
Origin
Unknown
USA, Australia
Discoverer
Unknown
Tornebohm
Etymology
From French anorthose plagioclase + -ite1
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
Not Applicable
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Foliated, Glassy
Earthy, Mud-rich, Rough
Color
Black, Bluish - Grey, Brown, Green, Grey, Light Greenish Grey, Pink, White
Black, Brown, Colourless, Green, Grey, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
No
Yes
Stain Resistant
No
No
Wind Resistant
Yes
Yes
Acid Resistant
No
Yes
Appearance
Layered, Banded, Veined and Shiny
Dull
Uses
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Medical Industry
Not Yet Used
Not Applicable
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Creating Artwork, Curling
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Types
Proterozoic Anorthosite and Archean Anorthosite
Endoskarns
Features
Generally rough to touch, Is one of the oldest rock
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Used
Used
Fossils
Absent
Absent
Formation
Formation
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Composition
Mineral Content
Amphibole, Clinopyroxene, Ilmenite, Magnetite, Olivine, Orthopyroxene
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Ca, CaO, Chromium(III) Oxide, MgO, Sulfur Trioxide
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Transformation
Metamorphism
Yes
Yes
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
Yes
No
Types of Weathering
Biological Weathering
Not Applicable
Erosion
Yes
No
Types of Erosion
Chemical Erosion, Wind Erosion
Not Applicable
Properties
Physical Properties
Hardness
5-6
6.5
Grain Size
Coarse Grained
Fine Grained
Fracture
Irregular
Irregular
Streak
White
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Pearly to Subvitreous
Waxy and Dull
Cleavage
Irregular
Slaty
Toughness
Not Available
2.4
Specific Gravity
2.62-2.82
2.86
Transparency
Translucent
Opaque
Density
2.7-4 g/cm3
2.8-2.9 g/cm3
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K
15
0.92 kJ/Kg K
10
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant
Reserves
Deposits in Eastern Continents
Asia
Not Yet Found
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Not Yet Found
South Africa, Western Africa
Europe
Bulgaria, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Malta, Poland, Portugal, Romania, Slovenia, Spain, Sweden, The Czech Republic
United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada
Canada
South America
Bolivia, Colombia
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
Central Australia, South Australia, Western Australia
Central Australia, Western Australia
All about Anorthosite and Skarn Properties
Know all about Anorthosite and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Anorthosite belongs to Igneous Rocks while Skarn belongs to Metamorphic Rocks.Texture of Anorthosite is Foliated, Glassy whereas that of Skarn is Earthy, Mud-rich, Rough. Anorthosite appears Layered, Banded, Veined and Shiny and Skarn appears Dull. The luster of Anorthosite is pearly to subvitreous while that of Skarn is waxy and dull. Anorthosite is available in black, bluish - grey, brown, green, grey, light greenish grey, pink, white colors whereas Skarn is available in black, brown, colourless, green, grey, white colors. The commercial uses of Anorthosite are creating artwork, curling and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).
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