Skarn and Mylonite
Definition
Definition
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
History
Origin
USA, Australia
New Zealand
Discoverer
Tornebohm
Unknown
Etymology
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
From Greek mulōn mill + -ite
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Earthy, Mud-rich, Rough
Foliated
Color
Black, Brown, Colourless, Green, Grey, White
Black to Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
No
No
Wind Resistant
Yes
No
Acid Resistant
Yes
No
Appearance
Dull
Dull, Banded and Foilated
Uses
Architecture
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
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
for Road Aggregate, Landscaping, Roadstone
Medical Industry
Not Applicable
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Other Uses
Commercial Uses
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Creating Artwork, Gemstone, Jewelry
Types
Types
Endoskarns
Blastomylonites, Ultramylonites and Phyllonites
Features
Host Rock for Lead, Zinc and Copper Deposits
Surfaces are often shiny
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Used
Fossils
Absent
Absent
Formation
Formation
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.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Composition
Mineral Content
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Porphyroblasts
Compound Content
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Transformation
Metamorphism
Yes
No
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Weathering
No
Yes
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
No
Yes
Types of Erosion
Not Applicable
Chemical Erosion, Sea Erosion, Wind Erosion
Properties
Physical Properties
Hardness
6.5
3-4
Grain Size
Fine Grained
Fine Grained
Fracture
Irregular
Conchoidal
Streak
Light to dark brown
White
Porosity
Less Porous
Highly Porous
Luster
Waxy and Dull
Shiny
Compressive Strength
Not Available
1.28 N/mm2
32
Cleavage
Slaty
Conchoidal
Toughness
2.4
Not Available
Specific Gravity
2.86
2.97-3.05
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.6-4.8 g/cm3
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K
10
1.50 kJ/Kg K
3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
China, India, Indonesia, Saudi Arabia, South Korea
Africa
South Africa, Western Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Europe
United Kingdom
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada
USA
South America
Brazil, Colombia, Paraguay
Not Yet Found
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Central Australia, Western Australia
All about Skarn and Mylonite Properties
Know all about Skarn and Mylonite properties here. All properties of rocks are important as they define the type of rock and its application. Skarn and Mylonite belong to Metamorphic Rocks.Texture of Skarn is Earthy, Mud-rich, Rough whereas that of Mylonite is Foliated. Skarn appears Dull and Mylonite appears Dull, Banded and Foilated. The luster of Skarn is waxy and dull while that of Mylonite is shiny. Skarn is available in black, brown, colourless, green, grey, white colors whereas Mylonite is available in black to grey colors. The commercial uses of Skarn and Mylonite are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).
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