Definition
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
History
Origin
New Zealand
-
Discoverer
Unknown
Unknown
Etymology
From Greek mulōn mill + -ite
From French schiste, Greek skhistos i.e. split
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated
Foliated, Platy
Color
Black to Grey
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull, Banded and Foilated
Layered and Shiny
Architecture
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Floor Tiles, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
-
Industry
Construction Industry
for Road Aggregate, Landscaping, Roadstone
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments
Artifacts
Other Uses
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Used in aquariums, Writing Slates
Types
Blastomylonites, Ultramylonites and Phyllonites
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Features
Surfaces are often shiny
Easily splits into thin plates, Smooth to touch
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
Composition
Mineral Content
Porphyroblasts
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Compound Content
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
CaO, Carbon Dioxide, MgO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Physical Properties
Hardness
3-43.5-4
1
7
👆🏻
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White
White
Porosity
Highly Porous
Highly Porous
Luster
Shiny
Shiny
Compressive Strength
1.28 N/mm2150.00 N/mm2
0.15
450
👆🏻
Cleavage
Conchoidal
Slaty
Toughness
-
1.5
Specific Gravity
2.97-3.052.5-2.9
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.6-4.8 g/cm32.8-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
1.50 kJ/Kg K0.70 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Impact Resistant, Pressure Resistant, Water Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Saudi Arabia, South Korea
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Europe
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Others
-
-
Deposits in Western Continents
North America
USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
-
Brazil, Colombia, Guyana
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New South Wales, New Zealand, Queensland