Schist and Mylonite
Definition
Definition
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
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
Unknown
New Zealand
Discoverer
Unknown
Unknown
Etymology
From French schiste, Greek skhistos i.e. split
From Greek mulōn mill + -ite
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Foliated, Platy
Foliated
Color
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Black to Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
No
Yes
Stain Resistant
No
No
Wind Resistant
No
No
Acid Resistant
No
No
Appearance
Layered and Shiny
Dull, Banded and Foilated
Uses
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Not Yet Used
Curbing
Industry
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
for Road Aggregate, Landscaping, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments
Other Uses
Commercial Uses
Used in aquariums, Writing Slates
Creating Artwork, Gemstone, Jewelry
Types
Types
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Blastomylonites, Ultramylonites and Phyllonites
Features
Easily splits into thin plates, Smooth to touch
Surfaces are often shiny
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Used
Used
Petroglyphs
Used
Used
Figurines
Not Yet Used
Used
Fossils
Absent
Absent
Formation
Formation
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Composition
Mineral Content
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Porphyroblasts
Compound Content
CaO, Carbon Dioxide, MgO
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Transformation
Metamorphism
No
No
Types of Metamorphism
Not Applicable
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Properties
Physical Properties
Hardness
3.5-4
3-4
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Streak
White
White
Porosity
Highly Porous
Highly Porous
Luster
Shiny
Shiny
Compressive Strength
Not Available
1.28 N/mm2
32
Cleavage
Slaty
Conchoidal
Toughness
1.5
Not Available
Specific Gravity
2.5-2.9
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
Not Available
1.50 kJ/Kg K
3
Resistance
Impact Resistant, Pressure Resistant, Water Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Reserves
Deposits in Eastern Continents
Asia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
China, India, Indonesia, Saudi Arabia, South Korea
Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Europe
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
USA
South America
Brazil, Colombia, Guyana
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland
Central Australia, Western Australia
All about Schist and Mylonite Properties
Know all about Schist and Mylonite properties here. All properties of rocks are important as they define the type of rock and its application. Schist and Mylonite belong to Metamorphic Rocks.Texture of Schist is Foliated, Platy whereas that of Mylonite is Foliated. Schist appears Layered and Shiny and Mylonite appears Dull, Banded and Foilated. The luster of Schist and Mylonite is shiny. Schist is available in black, blue, brown, dark brown, green, grey, silver colors whereas Mylonite is available in black to grey colors. The commercial uses of Schist are used in aquariums, writing slates and that of Mylonite are creating artwork, gemstone, jewelry.
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