Mylonite and Nephelinite
Definition
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
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
History
Origin
New Zealand
Brazil
Discoverer
Unknown
Unknown
Etymology
From Greek mulōn mill + -ite
from French néphéline, from Greek nephelē
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Not Applicable
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Foliated
Aphanitic
Color
Black to Grey
Black, Brown, Colourless, Green, Grey, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
No
Yes
Wind Resistant
No
Yes
Acid Resistant
No
Yes
Appearance
Dull, Banded and Foilated
Skeletal
Uses
Architecture
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
for Road Aggregate, Landscaping, Roadstone
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Types
Types
Blastomylonites, Ultramylonites and Phyllonites
Peralkaline Nephelinite
Features
Surfaces are often shiny
Host Rock for Lead
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
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Used
Used
Fossils
Absent
Absent
Formation
Formation
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Nephelinite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Composition
Mineral Content
Porphyroblasts
Clinopyroxene, Nepheline, Plagioclase
Compound Content
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Ca, CaO, Carbon, Cl, MgO
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Contact Metamorphism
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, Sea Erosion, Wind Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
3-4
6.5
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Flat
Streak
White
White
Porosity
Highly Porous
Less Porous
Luster
Shiny
Vitreous to Metallic
Compressive Strength
1.28 N/mm2
32
35.00 N/mm2
29
Cleavage
Conchoidal
Imperfect
Toughness
Not Available
2.7
Specific Gravity
2.97-3.05
2.4-2.9
Transparency
Opaque
Opaque
Density
2.6-4.8 g/cm3
2.5-3 g/cm3
Thermal Properties
Specific Heat Capacity
1.50 kJ/Kg K
3
0.88 kJ/Kg K
13
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Indonesia, Saudi Arabia, South Korea
Japan
Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Rwanda, Tanzania
Europe
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Not Yet Found
Others
Not Yet Found
Hawaii Islands
Deposits in Western Continents
North America
USA
Canada, USA
South America
Not Yet Found
Colombia
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Not Yet Found
All about Mylonite and Nephelinite Properties
Know all about Mylonite and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Mylonite belongs to Metamorphic Rocks while Nephelinite belongs to Igneous Rocks.Texture of Mylonite is Foliated whereas that of Nephelinite is Aphanitic. Mylonite appears Dull, Banded and Foilated and Nephelinite appears Skeletal. The luster of Mylonite is shiny while that of Nephelinite is vitreous to metallic. Mylonite is available in black to grey colors whereas Nephelinite is available in black, brown, colourless, green, grey, white colors. The commercial uses of Mylonite are creating artwork, gemstone, jewelry and that of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).
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