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Gneiss and Syenite


Syenite and Gneiss


Definition

Definition
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   
Syenite is a coarse-grained igneous rock which is composed mainly of alkali feldspar and various ferromagnesian minerals   

History
  
  

Discoverer
Unknown   
Unknown   

Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)   
From French syénite, from Latin Syenites (lapis ) (stone) of Syene   

Class
Metamorphic Rocks   
Igneous Rocks   

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

Family
  
  

Group
Not Applicable   
Plutonic   

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

Texture

Texture
Banded, Foliated, Platy   
Earthy   

Color
Black, Brown, Pink, Red, White   
Brown, Buff, Cream, Green, Grey, Pink, White   

Maintenance
More   
Less   

Durability
Durable   
Durable   

Water Resistant
Yes   
Yes   

Scratch Resistant
Yes   
Yes   

Stain Resistant
Yes   
No   

Wind Resistant
Yes   
Yes   

Acid Resistant
No   
Yes   

Appearance
Foliated   
Banded and Foilated   

Uses

Architecture
  
  

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

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

Other Architectural Uses
Curbing   
Curbing   

Industry
  
  

Construction Industry
As Dimension Stone   
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts   
Artifacts, Monuments, Sculpture, Small Figurines   

Other Uses
  
  

Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums   
Cemetery Markers, Creating Artwork   

Types

Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.   
Shonkinite   

Features
Generally rough to touch, Is one of the oldest rock   
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable   

Archaeological Significance
  
  

Monuments
Used   
Used   

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

Sculpture
Not Yet Used   
Used   

Famous Sculptures
Not Applicable   
Data Not Available   

Pictographs
Not Used   
Used   

Petroglyphs
Not Used   
Used   

Figurines
Not Yet Used   
Used   

Fossils
Absent   
Absent   

Formation

Formation
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.   
Syenites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.   

Composition
  
  

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

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

Transformation
  
  

Metamorphism
Yes   
Yes   

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

Weathering
Yes   
Yes   

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

Erosion
Yes   
Yes   

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

Properties

Physical Properties
  
  

Hardness
7   
5.5-6   

Grain Size
Medium to Coarse Grained   
Medium to Fine Coarse Grained   

Fracture
Irregular   
Not Available   

Streak
White   
White   

Porosity
Very Less Porous   
Less Porous   

Luster
Dull   
Subvitreous to Dull   

Compressive Strength
125.00 N/mm2   
17
150.00 N/mm2   
14

Cleavage
Poor   
Perfect   

Toughness
1.2   
Not Available   

Specific Gravity
2.5-2.7   
2.6-2.7   

Transparency
Translucent to Opaque   
Opaque   

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

Thermal Properties
  
  

Specific Heat Capacity
Not Available   
0.92 kJ/Kg K   
10

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

Reserves

Deposits in Eastern Continents
  
  

Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia   
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam   

Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo   
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa   

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

Others
Not Yet Found   
Not Yet Found   

Deposits in Western Continents
  
  

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

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

Deposits in Oceania Continent
  
  

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

Summary >>
<< Reserves

All about Gneiss and Syenite Properties

Know all about Gneiss and Syenite properties here. All properties of rocks are important as they define the type of rock and its application. Gneiss belongs to Metamorphic Rocks while Syenite belongs to Igneous Rocks.Texture of Gneiss is Banded, Foliated, Platy whereas that of Syenite is Earthy. Gneiss appears Foliated and Syenite appears Banded and Foilated. The luster of Gneiss is dull while that of Syenite is subvitreous to dull. Gneiss is available in black, brown, pink, red, white colors whereas Syenite is available in brown, buff, cream, green, grey, pink, white colors. The commercial uses of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums and that of Syenite are cemetery markers, creating artwork.

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