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
Pyroxenite is a dark, greenish, granular intrusive igneous rock consisting mainly of pyroxenes and olivine
1.2 History
1.2.1 Origin
1.2.2 Discoverer
1.3 Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From pyro- fire + Greek xenos stranger as the mineral group was new to igneous rocks
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
Clastic, Granular, Phaneritic, Porphyritic
2.2 Color
Black, Brown, Pink, Red, White
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
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
Layered, Banded, Veined and Shiny
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration, Kitchens
3.1.2 Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing 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
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.
Clinopyroxenites, Orthopyroxenites and Websterites
4.2 Features
Generally rough to touch, Is one of the oldest rock
Generally rough to touch, Host rock for Diamond, Is one of the oldest rock
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Konark Sun Temple in India, Washington Monument, US
Not Applicable
4.3.3 Sculpture
Not Yet Used
Not Yet Used
4.3.4 Famous Sculptures
Not Applicable
Not Applicable
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
Not Yet Used
Not Yet Used
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.
Pyroxenites are ultramafic igneous rocks which are made up of minerals of the pyroxene group, such as augite and diopside, hypersthene, bronzite or enstatite.
5.2 Composition
5.2.1 Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, 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
Burial Metamorphism, Impact Metamorphism, Regional Metamorphism
5.3.3 Weathering
5.3.4 Types of Weathering
Biological Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Chemical Erosion, Coastal Erosion, Water 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
White
White, Greenish White or Grey
6.1.5 Porosity
Very Less Porous
Less Porous
6.1.6 Luster
Dull
Dull to Vitreous to Submetallic
6.1.7 Compressive Strength
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/cm33.1-3.6 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