1 Definition
1.1 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
Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt
1.2 History
1.2.1 Origin
1.2.2 Discoverer
Unknown
Christian Leopold von Buch
1.3 Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From Latin glaber bare, smooth, bald
1.4 Class
Metamorphic Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
2 Texture
2.1 Texture
Banded, Foliated, Platy
Phaneritic
2.2 Color
Black, Brown, Pink, Red, White
Dark Grey to Black
2.3 Maintenance
2.4 Durability
2.4.1 Water Resistant
2.4.2 Scratch Resistant
2.4.3 Stain Resistant
2.4.4 Wind Resistant
2.4.5 Acid Resistant
2.5 Appearance
Foliated
Veined and Shiny
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
3.1.2 Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
3.1.3 Other Architectural Uses
3.2 Industry
3.2.1 Construction Industry
As Dimension Stone
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
3.2.2 Medical Industry
Not Yet Used
Not Yet Used
3.3 Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
3.4 Other Uses
3.4.1 Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
4 Types
4.1 Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Not Available
4.2 Features
Generally rough to touch, Is one of the oldest rock
Smooth to touch
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Konark Sun Temple in India, Washington Monument, US
Data Not Available
4.3.3 Sculpture
4.3.4 Famous Sculptures
Not Applicable
Data Not Available
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
4.4 Fossils
5 Formation
5.1 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.
Gabbro, a mafic rock, forms due to cooling and crystallization of magma underneath Earth's surface.
5.2 Composition
5.2.1 Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Augite, Olivine, Plagioclase, Pyroxene
5.2.2 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, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
5.3 Transformation
5.3.1 Metamorphism
5.3.2 Types of Metamorphism
Impact Metamorphism
Impact Metamorphism
5.3.3 Weathering
5.3.4 Types of Weathering
Biological Weathering, Mechanical Weathering
Chemical Weathering
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Coastal Erosion
6 Properties
6.1 Physical Properties
6.1.1 Hardness
6.1.2 Grain Size
Medium to Coarse Grained
Coarse Grained
6.1.3 Fracture
6.1.4 Streak
6.1.5 Porosity
Very Less Porous
Highly Porous
6.1.6 Luster
6.1.7 Compressive Strength
125.00 N/mm2225.00 N/mm2
0.15
450
6.1.8 Cleavage
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
Translucent to Opaque
Opaque
6.1.12 Density
2.6-2.9 g/cm32.7-3.3 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
6.2.2 Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
7 Reserves
7.1 Deposits in Eastern Continents
7.1.1 Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
India, Russia
7.1.2 Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
South Africa
7.1.3 Europe
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom
Germany, Greece, Italy, Scotland, Turkey
7.1.4 Others
7.2 Deposits in Western Continents
7.2.1 North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, USA
7.2.2 South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil, Colombia, Venezuela
7.3 Deposits in Oceania Continent
7.3.1 Australia
New South Wales, New Zealand, Queensland, Victoria
New Zealand, Queensland