Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Carbonatite is intrusive or extrusive igneous rock which is defined by mineralogic composition, consisting of greater than 50 percent carbonate minerals
History
Origin
Brazil
Tanzania
Discoverer
Unknown
Unknown
Etymology
from French néphéline, from Greek nephelē
From any intrusive igneous rock, having a majority of carbonate minerals
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Plutonic
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic
Granular, Poikiloblastic
Color
Black, Brown, Green, Grey, White
Black, Brown, Green, Grey, Pink, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Skeletal
Dull, Banded and Foilated
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Medical Industry
-
Taken as a Supplement for Calcium or Magnesium
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Other Uses
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux
Types
Peralkaline Nephelinite
Carbonatite
Features
Host Rock for Lead
Available in lots of colors, Generally rough to touch, Is one of the oldest 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.
Carbonatites are intrusive or extrusive igneous rocks which are defined by mineralogic composition consisting of greater than 50 percent carbonate minerals and are formed due to low degrees of partial melting of rocks.
Composition
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Ancylite, Apatite, Barite, Fluorite, Magnetite, Natrolite, Sodalite
Compound Content
Ca, CaO, Carbon, Cl, MgO
CaO, Carbon Dioxide, Sodium Oxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Contact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Wind Erosion
Physical Properties
Hardness
6.53
1
7
👆🏻
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Flat
Conchoidal
Streak
White
White
Porosity
Less Porous
Less Porous
Luster
Vitreous to Metallic
Subvitreous to Dull
Compressive Strength
35.00 N/mm275.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
2.7
1
Specific Gravity
2.4-2.92.86-2.87
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.5-3 g/cm32.84-2.86 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.88 kJ/Kg K0.51 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Water Resistant
Deposits in Eastern Continents
Asia
Japan
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
Rwanda, Tanzania
Namibia, Nigeria, South Africa
Europe
-
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
Hawaii Islands
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Colombia
Brazil
Deposits in Oceania Continent
Australia
-
New South Wales, New Zealand