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Tephrite and Gneiss


Gneiss and Tephrite


Definition

Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock   
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks   

History
  
  

Origin
Germany   
Unknown   

Discoverer
Van Tooren   
Unknown   

Etymology
From Greek tephra, ashes from Indo-European base, to burn   
From the Middle High German verb gneist (to spark; so called because the rock glitters)   

Class
Igneous Rocks   
Metamorphic Rocks   

Sub-Class
Durable Rock, Hard Rock   
Durable Rock, Hard Rock   

Family
  
  

Group
Volcanic   
Not Applicable   

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

Texture

Texture
Aphanitic to Porphyritic   
Banded, Foliated, Platy   

Color
Black, Brown, Colourless, Green, Grey, White   
Black, Brown, Pink, Red, White   

Maintenance
Less   
More   

Durability
Durable   
Durable   

Water Resistant
Yes   
Yes   

Scratch Resistant
Yes   
Yes   

Stain Resistant
No   
Yes   

Wind Resistant
Yes   
Yes   

Acid Resistant
No   
No   

Appearance
Vesicular   
Foliated   

Uses

Architecture
  
  

Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration   
Countertops, Decorative Aggregates, Flooring, Interior Decoration   

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

Other Architectural Uses
Curbing   
Curbing   

Industry
  
  

Construction Industry
Landscaping   
As Dimension Stone   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts, Sculpture   
Artifacts   

Other Uses
  
  

Commercial Uses
Production of Lime, Soil Conditioner   
Cemetery Markers, Jewelry, Tombstones, Used in aquariums   

Types

Types
Not Available   
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.   

Features
Host Rock for Lead   
Generally rough to touch, Is one of the oldest rock   

Archaeological Significance
  
  

Monuments
Not Yet Used   
Used   

Famous Monuments
Not Applicable   
Konark Sun Temple in India, Washington Monument, US   

Sculpture
Used   
Not Yet Used   

Famous Sculptures
Data Not Available   
Not Applicable   

Pictographs
Not Used   
Not Used   

Petroglyphs
Not Used   
Not 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.   
Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.   

Composition
  
  

Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene   
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon   

Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide   
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide   

Transformation
  
  

Metamorphism
Yes   
Yes   

Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism   
Impact Metamorphism   

Weathering
Yes   
Yes   

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

Erosion
Yes   
Yes   

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

Properties

Physical Properties
  
  

Hardness
6.5   
7   

Grain Size
Medium to Fine Coarse Grained   
Medium to Coarse Grained   

Fracture
Uneven   
Irregular   

Streak
Bluish Black   
White   

Porosity
Very Less Porous   
Very Less Porous   

Luster
Subvitreous to Dull   
Dull   

Compressive Strength
90.00 N/mm2   
22
125.00 N/mm2   
17

Cleavage
Crenulation and Pervasive   
Poor   

Toughness
2.4   
1.2   

Specific Gravity
2.86   
2.5-2.7   

Transparency
Opaque   
Translucent to Opaque   

Density
2.8-2.9 g/cm3   
2.6-2.9 g/cm3   

Thermal Properties
  
  

Specific Heat Capacity
0.92 kJ/Kg K   
10
Not Available   

Resistance
Heat Resistant, Impact Resistant   
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
Not Yet Found   
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia   

Africa
Namibia, Uganda   
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo   

Europe
Germany, Hungary, Italy, Portugal, Spain   
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom   

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   
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela   

Deposits in Oceania Continent
  
  

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

Summary >>
<< Reserves

All about Tephrite and Gneiss Properties

Know all about Tephrite and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Gneiss is Banded, Foliated, Platy. Tephrite appears Vesicular and Gneiss appears Foliated. The luster of Tephrite is subvitreous to dull while that of Gneiss is dull. Tephrite is available in black, brown, colourless, green, grey, white colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.

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