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Tephrite and Schist


Schist and Tephrite


Definition

Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock   
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation   

History
  
  

Origin
Germany   
Unknown   

Discoverer
Van Tooren   
Unknown   

Etymology
From Greek tephra, ashes from Indo-European base, to burn   
From French schiste, Greek skhistos i.e. split   

Class
Igneous Rocks   
Metamorphic Rocks   

Sub-Class
Durable Rock, Hard Rock   
Durable Rock, Medium Hardness Rock   

Family
  
  

Group
Volcanic   
Not Applicable   

Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock   
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock   

Texture

Texture
Aphanitic to Porphyritic   
Foliated, Platy   

Color
Black, Brown, Colourless, Green, Grey, White   
Black, Blue, Brown, Dark Brown, Green, Grey, Silver   

Maintenance
Less   
Less   

Durability
Durable   
Durable   

Water Resistant
Yes   
Yes   

Scratch Resistant
Yes   
No   

Stain Resistant
No   
No   

Wind Resistant
Yes   
No   

Acid Resistant
No   
No   

Appearance
Vesicular   
Layered and Shiny   

Uses

Architecture
  
  

Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration   
Decorative Aggregates, Floor Tiles, Interior Decoration   

Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings   
Garden Decoration, Paving Stone   

Other Architectural Uses
Curbing   
Not Yet Used   

Industry
  
  

Construction Industry
Landscaping   
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts, Sculpture   
Artifacts   

Other Uses
  
  

Commercial Uses
Production of Lime, Soil Conditioner   
Used in aquariums, Writing Slates   

Types

Types
Not Available   
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.   

Features
Host Rock for Lead   
Easily splits into thin plates, Smooth to touch   

Archaeological Significance
  
  

Monuments
Not Yet Used   
Not Yet Used   

Famous Monuments
Not Applicable   
Not Applicable   

Sculpture
Used   
Not Yet Used   

Famous Sculptures
Data Not Available   
Not Applicable   

Pictographs
Not Used   
Used   

Petroglyphs
Not Used   
Used   

Figurines
Used   
Not Yet Used   

Fossils
Absent   
Absent   

Formation

Formation
Tephrite 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.   
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.   

Composition
  
  

Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene   
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc   

Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide   
CaO, Carbon Dioxide, MgO   

Transformation
  
  

Metamorphism
Yes   
No   

Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism   
Not Applicable   

Weathering
Yes   
Yes   

Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering   
Biological Weathering, Chemical Weathering, Mechanical Weathering   

Erosion
Yes   
Yes   

Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion   
Chemical Erosion, Coastal Erosion, Glacier Erosion   

Properties

Physical Properties
  
  

Hardness
6.5   
3.5-4   

Grain Size
Medium to Fine Coarse Grained   
Medium to Fine Coarse Grained   

Fracture
Uneven   
Conchoidal   

Streak
Bluish Black   
White   

Porosity
Very Less Porous   
Highly Porous   

Luster
Subvitreous to Dull   
Shiny   

Compressive Strength
90.00 N/mm2   
22
Not Available   

Cleavage
Crenulation and Pervasive   
Slaty   

Toughness
2.4   
1.5   

Specific Gravity
2.86   
2.5-2.9   

Transparency
Opaque   
Opaque   

Density
2.8-2.9 g/cm3   
2.8-2.9 g/cm3   

Thermal Properties
  
  

Specific Heat Capacity
0.92 kJ/Kg K   
10
Not Available   

Resistance
Heat Resistant, Impact Resistant   
Impact Resistant, Pressure Resistant, Water Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
Not Yet Found   
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam   

Africa
Namibia, Uganda   
Egypt, Ethiopia, Morocco, Nigeria, South Africa   

Europe
Germany, Hungary, Italy, Portugal, Spain   
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland   

Others
Not Yet Found   
Not Yet Found   

Deposits in Western Continents
  
  

North America
USA   
Canada, Costa Rica, Cuba, Mexico, Panama, USA   

South America
Not Yet Found   
Brazil, Colombia, Guyana   

Deposits in Oceania Continent
  
  

Australia
New Zealand, Western Australia   
New South Wales, New Zealand, Queensland   

Summary >>
<< Reserves

All about Tephrite and Schist Properties

Know all about Tephrite and Schist properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Schist belongs to Metamorphic Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Schist is Foliated, Platy. Tephrite appears Vesicular and Schist appears Layered and Shiny. The luster of Tephrite is subvitreous to dull while that of Schist is shiny. Tephrite is available in black, brown, colourless, green, grey, white colors whereas Schist is available in black, blue, brown, dark brown, green, grey, silver colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Schist are used in aquariums, writing slates.

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