Definition
Peridotite is a dense, coarse-grained plutonic is the main constituent of the earth's mantle
  
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
  
History
  
  
Origin
Pike County, U.S
  
Brazil
  
Discoverer
Unknown
  
Unknown
  
Etymology
From French, from peridot + -ite
  
from French néphéline, from Greek nephelē
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Plutonic
  
Plutonic
  
Other Categories
Coarse Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Phaneritic
  
Aphanitic
  
Color
Dark Greenish - Grey
  
Black, Brown, Colourless, Green, Grey, White
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Rough and Shiny
  
Skeletal
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Interior Decoration
  
Decorative Aggregates, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
  
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Cobblestones
  
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
  
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
  
Types
Dunite, Wehrlite, Harzburgite, Lherzolite and Pyrolite
  
Peralkaline Nephelinite
  
Features
Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest rock
  
Host Rock for Lead
  
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
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Peridotites can be formed in two ways: as mantle rocks formed during the accretion and differentiation of the Earth or as cumulate rocks formed by precipitation of olivine and pyroxenes from basaltic magmas.
  
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.
  
Composition
  
  
Mineral Content
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
  
Clinopyroxene, Nepheline, Plagioclase
  
Compound Content
Ca, Fe, Mg, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
  
Ca, CaO, Carbon, Cl, MgO
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Contact Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion
  
Chemical Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
5.5-6
  
6.5
  
Grain Size
Coarse Grained
  
Fine Grained
  
Fracture
Irregular
  
Flat
  
Streak
White
  
White
  
Porosity
Less Porous
  
Less Porous
  
Luster
Shiny
  
Vitreous to Metallic
  
Compressive Strength
107.55 N/mm2
  
19
35.00 N/mm2
  
29
Cleavage
Imperfect
  
Imperfect
  
Toughness
2.1
  
2.7
  
Specific Gravity
3-3.01
  
2.4-2.9
  
Transparency
Translucent to Opaque
  
Opaque
  
Density
3.1-3.4 g/cm3
  
2.5-3 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
1.26 kJ/Kg K
  
5
0.88 kJ/Kg K
  
13
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant
  
Deposits in Eastern Continents
  
  
Asia
China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey
  
Japan
  
Africa
Morocco, South Africa
  
Rwanda, Tanzania
  
Europe
Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland, Venezuela
  
Not Yet Found
  
Others
Not Yet Found
  
Hawaii Islands
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Brazil
  
Colombia
  
Deposits in Oceania Continent
  
  
Australia
New Zealand, Western Australia
  
Not Yet Found