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Nephelinite and Adakite


Adakite and Nephelinite


Definition

Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).   
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs   

History
  
  

Origin
Brazil   
Adak, Aleutian Islands   

Discoverer
Unknown   
Defant and Drummond   

Etymology
from French néphéline, from Greek nephelē   
From Adak, Aleutian Islands   

Class
Igneous Rocks   
Igneous Rocks   

Sub-Class
Durable Rock, Hard Rock   
Durable Rock, Medium Hardness Rock   

Family
  
  

Group
Plutonic   
Volcanic   

Other Categories
Fine Grained Rock, Opaque Rock   
Fine Grained Rock, Medium Grained Rock, Opaque Rock   

Texture

Texture
Aphanitic   
Porphyritic   

Color
Black, Brown, Colourless, Green, Grey, White   
Black, Brown, Light to Dark Grey   

Maintenance
Less   
Less   

Durability
Durable   
Durable   

Water Resistant
Yes   
No   

Scratch Resistant
Yes   
No   

Stain Resistant
Yes   
No   

Wind Resistant
Yes   
Yes   

Acid Resistant
Yes   
Yes   

Appearance
Skeletal   
Dull and Soft   

Uses

Architecture
  
  

Interior Uses
Decorative Aggregates, Homes, Interior Decoration   
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens   

Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone   
As Building Stone, As Facing Stone, Office Buildings   

Other Architectural Uses
Curbing   
Whetstones   

Industry
  
  

Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate   
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines   
Monuments, Sculpture, Small Figurines   

Other Uses
  
  

Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)   
Commemorative Tablets, Pottery, Used in aquariums   

Types

Types
Peralkaline Nephelinite   
Not Available   

Features
Host Rock for Lead   
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock   

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
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.   
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.   

Composition
  
  

Mineral Content
Clinopyroxene, Nepheline, Plagioclase   
Olivine, Plagioclase, Pyroxene   

Compound Content
Ca, CaO, Carbon, Cl, MgO   
Aluminium Oxide, MgO, Silicon Dioxide   

Transformation
  
  

Metamorphism
Yes   
Yes   

Types of Metamorphism
Contact Metamorphism   
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism   

Weathering
Yes   
Yes   

Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering   
Chemical Weathering, Mechanical Weathering   

Erosion
Yes   
Yes   

Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion   
Coastal Erosion, Sea Erosion, Water Erosion   

Properties

Physical Properties
  
  

Hardness
6.5   
3-4   

Grain Size
Fine Grained   
Fine to Medium Grained   

Fracture
Flat   
Conchoidal   

Streak
White   
Bluish Black   

Porosity
Less Porous   
Less Porous   

Luster
Vitreous to Metallic   
Grainy, Pearly and Vitreous   

Compressive Strength
35.00 N/mm2   
29
Not Available   

Cleavage
Imperfect   
Not Available   

Toughness
2.7   
Not Available   

Specific Gravity
2.4-2.9   
Not Available   

Transparency
Opaque   
Opaque   

Density
2.5-3 g/cm3   
Not Available   

Thermal Properties
  
  

Specific Heat Capacity
0.88 kJ/Kg K   
13
Not Available   

Resistance
Heat Resistant   
Heat Resistant, Pressure Resistant, Wear Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
Japan   
India, Russia   

Africa
Rwanda, Tanzania   
Ethiopia, Somalia, South Africa   

Europe
Not Yet Found   
Iceland   

Others
Hawaii Islands   
Not Yet Found   

Deposits in Western Continents
  
  

North America
Canada, USA   
Canada, USA   

South America
Colombia   
Brazil   

Deposits in Oceania Continent
  
  

Australia
Not Yet Found   
Not Yet Found   

Summary >>
<< Reserves

All about Nephelinite and Adakite Properties

Know all about Nephelinite and Adakite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Adakite belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Adakite is Porphyritic. Nephelinite appears Skeletal and Adakite appears Dull and Soft. The luster of Nephelinite is vitreous to metallic while that of Adakite is grainy, pearly and vitreous. Nephelinite is available in black, brown, colourless, green, grey, white colors whereas Adakite is available in black, brown, light to dark grey colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Adakite are commemorative tablets, pottery, used in aquariums.

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