Definition
A yellow sandstone which is flexible when cut into thin strips
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
-
-
Discoverer
Unknown
Unknown
Etymology
From the name of a mountain range where it was found; Itacolumi mountain in Brazil
From the Middle High German verb gneist (to spark; so called because the rock glitters)
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
-
-
Other Categories
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Granular, Rough
Banded, Foliated, Platy
Color
Beige, Black, Brown, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Black, Brown, Pink, Red, White
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Rough
Foliated
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens
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
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
As Dimension Stone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Other Uses
Commercial Uses
An Oil and Gas Reservoir, In aquifers, Petroleum reservoirs, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Types
Sandstone
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
Konark Sun Temple in India, Washington Monument, US
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Present
Absent
Formation
Itacolumite is a sedimentary rock which forms from cemented sand-sized clasts and is a type of sandstone.
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
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Impact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Physical Properties
Hardness
6-77
1
7
👆🏻
Grain Size
Coarse or Fine
Medium to Coarse Grained
Fracture
Conchoidal
Irregular
Streak
White
White
Porosity
Highly Porous
Very Less Porous
Luster
Dull
Dull
Compressive Strength
95.00 N/mm2125.00 N/mm2
0.15
450
👆🏻
Cleavage
Perfect
-
Toughness
2.6
1.2
Specific Gravity
2.2-2.82.5-2.7
0
8.4
👆🏻
Transparency
Opaque
Translucent to Opaque
Density
2.2-2.8 g/cm32.6-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K0.70 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
Africa
Namibia, Nigeria, South Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom
Others
Greenland
-
Deposits in Western Continents
North America
Canada, USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
Brazil
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
New South Wales, New Zealand, Queensland, Victoria