Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Origin
Hawaii Islands
Brazil
Discoverer
Unknown
Unknown
Etymology
From Greek pikros bitter + -ite, 19th century
from French néphéline, from Greek nephelē
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy, Rough
Aphanitic
Color
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
Black, Brown, Colourless, Green, Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Shiny
Skeletal
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Types
Oceanite
Peralkaline Nephelinite
Features
Host Rock for Lead
Host Rock for Lead
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Formation
Picrite 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.
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.
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Clinopyroxene, Nepheline, Plagioclase
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Ca, CaO, Carbon, Cl, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Contact Metamorphism
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Streak
White, Greenish White or Grey
White
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Vitreous to Metallic
Cleavage
Imperfect
Imperfect
Specific Gravity
2.75-2.92
2.4-2.9
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
2.5-3 g/cm3
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Africa
South Africa
Rwanda, Tanzania
Europe
Iceland
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
Not Yet Found
Not Yet Found
All about Picrite and Nephelinite Properties
Know all about Picrite and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Nephelinite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Nephelinite is Aphanitic. Picrite appears Rough and Shiny and Nephelinite appears Skeletal. The luster of Picrite is subvitreous to dull while that of Nephelinite is vitreous to metallic. Picrite and Nephelinite are available in black, brown, colourless, green, grey, pink, white, yellow colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).