Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Discoverer
Unknown
Unknown
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
from French néphéline, from Greek nephelē
Class
Metamorphic 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
Color
Black, Brown, Green, Grey, Pink, White
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Skeletal
Interior Uses
Decorative Aggregates, Entryways, 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
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Gemstone
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Types
Cataclastic rock
Peralkaline Nephelinite
Features
Host Rock for Lead
Host Rock for Lead
Archaeological Significance
Formation
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
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
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Clinopyroxene, Nepheline, Plagioclase
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Ca, CaO, Carbon, Cl, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Contact Metamorphism
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Fine Grained
Streak
Light to dark brown
White
Porosity
Less Porous
Less Porous
Luster
Vitreous
Vitreous to Metallic
Specific Gravity
2.46-2.86
2.4-2.9
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
2.5-3 g/cm3
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Africa
Western Africa
Rwanda, Tanzania
Europe
Great Britain, Switzerland
-
Deposits in Western Continents
North America
-
Canada, USA
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
-
All about Pseudotachylite and Nephelinite Properties
Know all about Pseudotachylite and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Nephelinite belongs to Igneous Rocks.Texture of Pseudotachylite is Quench whereas that of Nephelinite is Aphanitic. Pseudotachylite appears Dull and Soft and Nephelinite appears Skeletal. The luster of Pseudotachylite is vitreous while that of Nephelinite is vitreous to metallic. Pseudotachylite and Nephelinite are available in black, brown, green, grey, pink, white colors. The commercial uses of Pseudotachylite are creating artwork, gemstone and that of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).