Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Charnockite is a variety of granite containing minerals like orthopyroxene, quartz, and feldspar
History
Origin
Brazil
Tamil Nadu, India
Discoverer
Unknown
T. H. Holland
Etymology
from French néphéline, from Greek nephelē
From Job Charnock, an administtrator of East India Company
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic
Granular
Color
Black, Brown, Green, Grey, White
Black, Grey, Orange, Pink, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Skeletal
Veined or Pebbled
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Bathrooms, Countertops, Decorative Aggregates, Entryways, Floor Tiles, Homes, Hotels, Kitchens, Stair Treads
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Bridges, Paving Stone, Garden Decoration, Office Buildings, Resorts
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Curling, Gemstone, Laboratory bench tops, Tombstones
Types
Peralkaline Nephelinite
Enderbite
Features
Host Rock for Lead
Available in Lots of Colors and Patterns, It is One of the Oldest, Strongest and Hardest 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.
Charnockite is an intrusive igneous rock which is very hard and is formed due to weathering of existing rocks.
Composition
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Olivine, Plagioclase, Pyroxene, 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
Burial Metamorphism, Contact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
6.56-7
1
7
👆🏻
Grain Size
Fine Grained
Coarse Grained
Fracture
Flat
-
Streak
White
White
Porosity
Less Porous
Very Less Porous
Luster
Vitreous to Metallic
-
Compressive Strength
35.00 N/mm2190.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
2.7
-
Specific Gravity
2.4-2.9-9999
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.5-3 g/cm32.6 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
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Japan
India
Africa
Rwanda, Tanzania
East Africa, Ethiopia, Madagascar, Morocco, Mozambique
Europe
-
Albania, Romania, Scotland, United Kingdom
Others
Hawaii Islands
-
Deposits in Western Continents
North America
Canada, USA
USA
South America
Colombia
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
-
Central Australia, Western Australia