Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
Origin
Brazil
USA, Australia
Discoverer
Unknown
Tornebohm
Etymology
from French néphéline, from Greek nephelē
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic
Earthy, Mud-rich, Rough
Color
Black, Brown, Green, Grey, White
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
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, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Peralkaline Nephelinite
Endoskarns
Features
Host Rock for Lead
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Ca, CaO, Carbon, Cl, MgO
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
-
Grain Size
Fine Grained
Fine Grained
Streak
White
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Vitreous to Metallic
Waxy and Dull
Specific Gravity
2.4-2.9
2.86
Transparency
Opaque
Opaque
Density
2.5-3 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Japan
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Rwanda, Tanzania
South Africa, Western Africa
Deposits in Western Continents
North America
Canada, USA
Canada
South America
Colombia
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
-
Central Australia, Western Australia
All about Nephelinite and Skarn Properties
Know all about Nephelinite and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite belongs to Igneous Rocks while Skarn belongs to Metamorphic Rocks.Texture of Nephelinite is Aphanitic whereas that of Skarn is Earthy, Mud-rich, Rough. Nephelinite appears Skeletal and Skarn appears Dull. The luster of Nephelinite is vitreous to metallic while that of Skarn is waxy and dull. Nephelinite and Skarn are available in black, brown, green, grey, white colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).