Definition
Dunite is a green to brownish coarse-grained igneous rock mainly consisting of olivine
  
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
  
History
  
  
Origin
New Zealand
  
Italy
  
Discoverer
Ferdinand von Hochstetter
  
Unknown
  
Etymology
From the name of Dun Mountain, New Zealand, + -ite1
  
From a Latin word tophous then in Italian tufo and finally tuff
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Plutonic
  
Volcanic
  
Other Categories
Coarse Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Phaneritic
  
Clastic, Pyroclastic
  
Color
Dark Greenish - Grey
  
Brown, Grey, Yellow
  
Maintenance
Less
  
More
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
No
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
No
  
Appearance
Rough and Shiny
  
Dull, Vesicular and Foilated
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Interior Decoration
  
Decorative Aggregates, Entryways, 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
  
Industry
  
  
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
  
Building houses or walls, Construction Aggregate
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
  
Creating Artwork
  
Types
Not Available
  
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
  
Features
Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest rock
  
Always found as volcanic pipes over deep continental crust
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Easter Island in the Polynesian Triangle, Pacific Ocean
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. It can be formed in two ways.
  
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.
  
Composition
  
  
Mineral Content
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
  
Calcite, Chlorite
  
Compound Content
Ca, CaO, Fe, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
  
Hydrogen Sulfide, Sulfur Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
3.5-4
  
4-6
  
Grain Size
Coarse Grained
  
Fine Grained
  
Fracture
Irregular
  
Uneven
  
Streak
White
  
White
  
Porosity
Less Porous
  
Highly Porous
  
Luster
Shiny
  
Vitreous to Dull
  
Compressive Strength
107.55 N/mm2
  
19
243.80 N/mm2
  
5
Cleavage
Imperfect
  
Not Available
  
Toughness
2.1
  
Not Available
  
Specific Gravity
3-3.01
  
2.73
  
Transparency
Translucent to Opaque
  
Opaque
  
Density
2.84-2.85 g/cm3
  
1-1.8 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
1.25 kJ/Kg K
  
6
0.20 kJ/Kg K
  
25
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey
  
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
  
Africa
Morocco, South Africa
  
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
  
Europe
Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland, Venezuela
  
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
  
Others
Not Yet Found
  
Antarctica, Hawaii Islands
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, Costa Rica, Panama, USA
  
South America
Argentina, Brazil, Colombia, Ecuador, Venezuela
  
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
  
Deposits in Oceania Continent
  
  
Australia
New Zealand, Western Australia
  
Central Australia, Western Australia