Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature
History
Origin
Brazil
USA
Discoverer
Unknown
Edgar Bailey
Etymology
from French néphéline, from Greek nephelē
From French schiste, Greek skhistos i.e. split
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic
Foliated
Color
Black, Brown, Green, Grey, White
Blue, Bluish - Grey, Purple, Shades of Blue
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Skeletal
Dull and Banded
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones
Types
Peralkaline Nephelinite
Metamorphic rock
Features
Host Rock for Lead
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
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.
Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.
Composition
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz
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
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Contact Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
6.53.5-4
1
7
👆🏻
Grain Size
Fine Grained
Fine to Medium Grained
Fracture
Flat
Conchoidal
Streak
White
White to Grey
Porosity
Less Porous
Highly Porous
Luster
Vitreous to Metallic
Dull
Compressive Strength
35.00 N/mm2220.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Slaty
Toughness
2.7
1.5
Specific Gravity
2.4-2.93-3.2
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.5-3 g/cm32.8-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.88 kJ/Kg K0.84 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant
Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Japan
Japan, Turkey
Africa
Rwanda, Tanzania
Egypt, Ethiopia, South Africa
Europe
-
France, Greece, Iceland
Others
Hawaii Islands
-
Deposits in Western Continents
North America
Canada, USA
USA
South America
Colombia
-
Deposits in Oceania Continent
Australia
-
New Zealand