Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance
Discoverer
Unknown
Unknown
Etymology
from French néphéline, from Greek nephelē
From Latin varius, speckled, variegated
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
Texture
Aphanitic
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Black, Brown, Colourless, Green, Grey, White
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Dull and Soft
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Cemetery Markers, Creating Artwork
Types
Peralkaline Nephelinite
Not Available
Features
Host Rock for Lead
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
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.
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Olivine, Plagioclase, Pyroxene
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
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
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Not Applicable
Grain Size
Fine Grained
Not Applicable
Streak
White
White to Grey
Porosity
Less Porous
Less Porous
Luster
Vitreous to Metallic
Not Available
Cleavage
Imperfect
Not Available
Specific Gravity
2.4-2.9
2.8-3
Transparency
Opaque
Opaque
Density
2.5-3 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
Rwanda, Tanzania
South Africa
Europe
Not Yet Found
Iceland
Others
Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Colombia
Brazil
Deposits in Oceania Continent
Australia
Not Yet Found
Not Yet Found
Nephelinite vs Variolite Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Nephelinite vs Variolite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Nephelinite and Properties of Variolite. Learn more about Nephelinite vs Variolite in the next section. The interior uses of Nephelinite include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Variolite include Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Nephelinite and Variolite, they have various applications in construction industry. The uses of Nephelinite in construction industry include As dimension stone, Cement manufacture, Construction aggregate, For road aggregate and that of Variolite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Nephelinite and Variolite
Here you can know more about Nephelinite and Variolite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Nephelinite and Variolite consists of mineral content and compound content. The mineral content of Nephelinite includes Clinopyroxene, Nepheline, Plagioclase and mineral content of Variolite includes Olivine, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Nephelinite vs Variolite, the texture, color and appearance plays an important role in determining the type of rock. Nephelinite is available in black, brown, colourless, green, grey, white colors whereas, Variolite is available in black, brown, light to dark grey colors. Appearance of Nephelinite is Skeletal and that of Variolite is Dull and Soft. Properties of rock is another aspect for Nephelinite vs Variolite. The hardness of Nephelinite is 6.5 and that of Variolite is 6. The types of Nephelinite are Peralkaline Nephelinite whereas types of Variolite are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Nephelinite is white while that of Variolite is white to grey. The specific heat capacity of Nephelinite is 0.88 kJ/Kg K and that of Variolite is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Nephelinite is heat resistant whereas Variolite is heat resistant, pressure resistant, wear resistant.