Greywacke and Skarn
Definition
Definition
Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
History
Origin
Unknown
USA, Australia
Discoverer
Unknown
Tornebohm
Etymology
From German Grauwacke, from grau grey + wacke
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Clastic
Earthy, Mud-rich, Rough
Color
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Black, Brown, Colourless, Green, Grey, White
Maintenance
Less
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
Dull
Dull
Uses
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Flooring, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing, Whetstones
Curbing
Industry
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Medical Industry
Not Yet Used
Not Applicable
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
As armour rock for sea walls, Petroleum reservoirs, Sea Defence, Tombstones
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Types
Not Available
Endoskarns
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Non-vesicular, Veined
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Used
Used
Fossils
Present
Absent
Formation
Formation
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Composition
Mineral Content
Augite, Biotite, Calcite, Chlorite, Clay, Clay Minerals, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
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
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
Yes
No
Types of Weathering
Biological Weathering, Chemical Weathering
Not Applicable
Erosion
Yes
No
Types of Erosion
Coastal Erosion, Sea Erosion, Wind Erosion
Not Applicable
Properties
Physical Properties
Hardness
6-7
6.5
Grain Size
Angular and Fine
Fine Grained
Fracture
Conchoidal
Irregular
Streak
White
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Dull
Waxy and Dull
Cleavage
Perfect
Slaty
Toughness
2.6
2.4
Specific Gravity
2.2-2.8
2.86
Transparency
Opaque
Opaque
Density
2.6-2.61 g/cm3
2.8-2.9 g/cm3
Thermal Properties
Specific Heat Capacity
Not Available
0.92 kJ/Kg K
10
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Namibia, Nigeria, South Africa
South Africa, Western Africa
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
United Kingdom
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada
South America
Brazil
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
Central Australia, Western Australia
All about Greywacke and Skarn Properties
Know all about Greywacke and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Greywacke belongs to Sedimentary Rocks while Skarn belongs to Metamorphic Rocks.Texture of Greywacke is Clastic whereas that of Skarn is Earthy, Mud-rich, Rough. Greywacke appears Dull and Skarn appears Dull. The luster of Greywacke is dull while that of Skarn is waxy and dull. Greywacke and Skarn are 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 Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).
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