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
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Discoverer
Unknown
Unknown
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From German Grauwacke, from grau grey + wacke
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Clastic
Color
Black, Brown, Pink, Red, White
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Decorative Aggregates, Floor Tiles, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing, Whetstones
Construction Industry
As Dimension Stone
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
As armour rock for sea walls, Petroleum reservoirs, Sea Defence, Tombstones
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Not Available
Features
Generally rough to touch, Is one of the oldest rock
Available in Lots of Colors and Patterns, Generally rough to touch, Non-vesicular, Veined
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Konark Sun Temple in India, Washington Monument, US
Not Applicable
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Not Yet Used
Used
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.
Graywacke rock is a type of sedimentary rock, which is also known as immature sandstone, which is indurated, dark grey and consisting of poorly sorted angular to sub-angular, sand-sized grains.
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Augite, Biotite, Calcite, Chlorite, Clay, Clay Minerals, Feldspar, 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, NaCl, CaO, Chromium(III) Oxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Impact Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Coastal Erosion, Sea Erosion, Wind Erosion
Grain Size
Medium to Coarse Grained
Angular and Fine
Fracture
Irregular
Conchoidal
Porosity
Very Less Porous
Highly Porous
Compressive Strength
Not Available
Specific Gravity
2.5-2.7
2.2-2.8
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm3
2.6-2.61 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
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
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, USA
South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
New South Wales, New Zealand
All about Gneiss and Greywacke Properties
Know all about Gneiss and Greywacke properties here. All properties of rocks are important as they define the type of rock and its application. Gneiss belongs to Metamorphic Rocks while Greywacke belongs to Sedimentary Rocks.Texture of Gneiss is Banded, Foliated, Platy whereas that of Greywacke is Clastic. Gneiss appears Foliated and Greywacke appears Dull. The luster of Gneiss and Greywacke is dull. Gneiss is available in black, brown, pink, red, white colors whereas Greywacke is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums and that of Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones.