1 Definition
1.1 Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance
1.2 History
1.2.1 Origin
1.2.2 Discoverer
1.3 Etymology
from French néphéline, from Greek nephelē
From Latin varius, speckled, variegated
1.4 Class
Igneous Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
2 Texture
2.1 Texture
Aphanitic
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
2.2 Color
Black, Brown, Colourless, Green, Grey, White
Black, Brown, Light to Dark Grey
2.3 Maintenance
2.4 Durability
2.4.1 Water Resistant
2.4.2 Scratch Resistant
2.4.3 Stain Resistant
2.4.4 Wind Resistant
2.4.5 Acid Resistant
2.5 Appearance
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Floor Tiles, Flooring, Homes, Hotels, Kitchens
3.1.2 Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration, Office Buildings
3.1.3 Other Architectural Uses
3.2 Industry
3.2.1 Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
3.2.2 Medical Industry
Not Yet Used
Not Yet Used
3.3 Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
3.4 Other Uses
3.4.1 Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Cemetery Markers, Creating Artwork
4 Types
4.1 Types
Peralkaline Nephelinite
Not Available
4.2 Features
Host Rock for Lead
Has High structural resistance against erosion and climate, Very fine grained rock
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Data Not Available
Data Not Available
4.3.3 Sculpture
4.3.4 Famous Sculptures
Data Not Available
Data Not Available
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
4.4 Fossils
5 Formation
5.1 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.
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
5.2 Composition
5.2.1 Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Olivine, Plagioclase, Pyroxene
5.2.2 Compound Content
Ca, CaO, Carbon, Cl, MgO
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
5.3 Transformation
5.3.1 Metamorphism
5.3.2 Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
5.3.3 Weathering
5.3.4 Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Not Applicable
6 Properties
6.1 Physical Properties
6.1.1 Hardness
6.1.2 Grain Size
Fine Grained
Not Applicable
6.1.3 Fracture
6.1.4 Streak
6.1.5 Porosity
6.1.6 Luster
Vitreous to Metallic
Not Available
6.1.7 Compressive Strength
35.00 N/mm237.50 N/mm2
0.15
450
6.1.8 Cleavage
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
6.1.12 Density
2.5-3 g/cm32.9-3.1 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
0.88 kJ/Kg K0.84 kJ/Kg K
0.14
3.2
6.2.2 Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
7 Reserves
7.1 Deposits in Eastern Continents
7.1.1 Asia
7.1.2 Africa
Rwanda, Tanzania
South Africa
7.1.3 Europe
7.1.4 Others
Hawaii Islands
Not Yet Found
7.2 Deposits in Western Continents
7.2.1 North America
7.2.2 South America
7.3 Deposits in Oceania Continent
7.3.1 Australia
Not Yet Found
Not Yet Found