Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Tonalite is a coarse-grained plutonic rock consisting mainly of sodic plagioclase, quartz, and hornblende or other mafic minerals with phaneritic texture
Origin
Brazil
Tonale, Italy
Discoverer
Unknown
Unknown
Etymology
from French néphéline, from Greek nephelē
From Tonale Pass, northern Italy, + -ite1
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic
Phaneritic
Color
Black, Brown, Colourless, Green, Grey, White
Black, Brown, Light to Dark Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Banded and Foilated
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, 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, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Sculpture
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Cemetery Markers, Creating Artwork
Types
Peralkaline Nephelinite
Dacite
Features
Host Rock for Lead
Is one of the oldest rock, Typically speckled black and white.
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not 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.
When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes tonalite with quartz as major mineral.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon
Compound Content
Ca, CaO, Carbon, Cl, MgO
NaCl, CaO, MgO, Silicon 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
Wind Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Streak
White
Bluish Black
Porosity
Less Porous
Very Less Porous
Luster
Vitreous to Metallic
Subvitreous to Dull
Compressive Strength
Not Available
Cleavage
Imperfect
Not Available
Specific Gravity
2.4-2.9
2.86-3
Transparency
Opaque
Opaque
Density
2.5-3 g/cm3
2.73 g/cm3
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Water Resistant
Deposits in Eastern Continents
Africa
Rwanda, Tanzania
Egypt
Europe
Not Yet Found
Finland, Germany, Italy, Romania, Sweden, Turkey
Others
Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Colombia
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, South Australia, Western Australia
All about Nephelinite and Tonalite Properties
Know all about Nephelinite and Tonalite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Tonalite belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Tonalite is Phaneritic. Nephelinite appears Skeletal and Tonalite appears Banded and Foilated. The luster of Nephelinite is vitreous to metallic while that of Tonalite is subvitreous to dull. Nephelinite is available in black, brown, colourless, green, grey, white colors whereas Tonalite is available in black, brown, light to dark grey, white colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Tonalite are cemetery markers, creating artwork.