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
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
  
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
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
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
  
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
  
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
  
Greywacke vs Skarn Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Greywacke vs Skarn characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Greywacke and Properties of Skarn. Learn more about Greywacke vs Skarn in the next section. The interior uses of Greywacke include Decorative aggregates, Floor tiles, Flooring, Homes and Interior decoration whereas the interior uses of Skarn include Decorative aggregates, Entryways and Interior decoration. Due to some exceptional properties of Greywacke and Skarn, they have various applications in construction industry. The uses of Greywacke in construction industry include Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Raw material for the manufacture of mortar and that of Skarn include 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.
More about Greywacke and Skarn
Here you can know more about Greywacke and Skarn. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Greywacke and Skarn consists of mineral content and compound content. The mineral content of Greywacke includes Augite, Biotite, Calcite, Chlorite, Clay, Clay Minerals, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz and mineral content of Skarn includes Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite. You can also check out the list of all Sedimentary Rocks. When we have to compare Greywacke vs Skarn, the texture, color and appearance plays an important role in determining the type of rock. Greywacke is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors whereas, Skarn is available in black, brown, colourless, green, grey, white colors. Appearance of Greywacke is Dull and that of Skarn is Dull. Properties of rock is another aspect for Greywacke vs Skarn. The hardness of Greywacke is 6-7 and that of Skarn is 6.5. The types of Greywacke are Not Available whereas types of Skarn are Endoskarns. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Greywacke is white while that of Skarn is light to dark brown. The specific heat capacity of Greywacke is Not Available and that of Skarn is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Greywacke is heat resistant, impact resistant, pressure resistant whereas Skarn is heat resistant.