Definition
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
  
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
Italy
  
USA, Australia
  
Discoverer
Unknown
  
Tornebohm
  
Etymology
From a Latin word tophous then in Italian tufo and finally tuff
  
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
  
Class
Igneous Rocks
  
Metamorphic Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Volcanic
  
Not Applicable
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Clastic, Pyroclastic
  
Earthy, Mud-rich, Rough
  
Color
Brown, Grey, Yellow
  
Black, Brown, Colourless, Green, Grey, White
  
Maintenance
More
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Dull, Vesicular and Foilated
  
Dull
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Entryways, 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
  
Curbing
  
Industry
  
  
Construction Industry
Building houses or walls, Construction Aggregate
  
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, Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture
  
Other Uses
  
  
Commercial Uses
Creating Artwork
  
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
  
Types
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
  
Endoskarns
  
Features
Always found as volcanic pipes over deep continental crust
  
Host Rock for Lead, Zinc and Copper Deposits
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Easter Island in the Polynesian Triangle, Pacific Ocean
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Tuff is formed when large masses of ash and sand which are mixed with hot gases are ejected by a volcano and avalanche rapidly down its slopes.
  
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
Calcite, Chlorite
  
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
  
Compound Content
Hydrogen Sulfide, Sulfur Dioxide
  
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
No
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Not Applicable
  
Erosion
Yes
  
No
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Not Applicable
  
Physical Properties
  
  
Hardness
4-6
  
6.5
  
Grain Size
Fine Grained
  
Fine Grained
  
Fracture
Uneven
  
Irregular
  
Streak
White
  
Light to dark brown
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Vitreous to Dull
  
Waxy and Dull
  
Compressive Strength
243.80 N/mm
2
  
5
Not Available
  
Cleavage
Not Available
  
Slaty
  
Toughness
Not Available
  
2.4
  
Specific Gravity
2.73
  
2.86
  
Transparency
Opaque
  
Opaque
  
Density
1-1.8 g/cm3
  
2.8-2.9 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.20 kJ/Kg K
  
25
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant
  
Deposits in Eastern Continents
  
  
Asia
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
  
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
  
Africa
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
  
South Africa, Western Africa
  
Europe
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
  
United Kingdom
  
Others
Antarctica, Hawaii Islands
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Costa Rica, Panama, USA
  
Canada
  
South America
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
  
Brazil, Colombia, Paraguay
  
Deposits in Oceania Continent
  
  
Australia
Central Australia, Western Australia
  
Central Australia, Western Australia
  
Tuff 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. Tuff vs Skarn characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Tuff and Properties of Skarn. Learn more about Tuff vs Skarn in the next section. The interior uses of Tuff include Decorative aggregates, Entryways, Flooring, Homes and Interior decoration whereas the interior uses of Skarn include Decorative aggregates, Entryways and Interior decoration. Due to some exceptional properties of Tuff and Skarn, they have various applications in construction industry. The uses of Tuff in construction industry include Building houses or walls, Construction aggregate 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 Tuff and Skarn
Here you can know more about Tuff and Skarn. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Tuff and Skarn consists of mineral content and compound content. The mineral content of Tuff includes Calcite, Chlorite and mineral content of Skarn includes Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite. You can also check out the list of all Igneous Rocks. When we have to compare Tuff vs Skarn, the texture, color and appearance plays an important role in determining the type of rock. Tuff is available in brown, grey, yellow colors whereas, Skarn is available in black, brown, colourless, green, grey, white colors. Appearance of Tuff is Dull, Vesicular and Foilated and that of Skarn is Dull. Properties of rock is another aspect for Tuff vs Skarn. The hardness of Tuff is 4-6 and that of Skarn is 6.5. The types of Tuff are Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite. 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 Tuff is white while that of Skarn is light to dark brown. The specific heat capacity of Tuff is 0.20 kJ/Kg K 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.Tuff is heat resistant, impact resistant, pressure resistant, wear resistant whereas Skarn is heat resistant.