Definition
Basalt is a common extrusive igneous rock formed by the rapid cooling of basaltic lava exposed at or very near the surface of Earth
  
Dunite is a green to brownish coarse-grained igneous rock mainly consisting of olivine
  
History
  
  
Origin
Egypt
  
New Zealand
  
Discoverer
Georgius Agricola
  
Ferdinand von Hochstetter
  
Etymology
From Late Latin Basaltes (variant of basanites ), very hard stone, which was imported from Ancient Greek Basanites
  
From the name of Dun Mountain, New Zealand, + -ite1
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Volcanic
  
Plutonic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Coarse Grained Rock, Opaque Rock
  
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
  
Phaneritic
  
Color
Black, Brown, Light to Dark Grey
  
Dark Greenish - Grey
  
Maintenance
More
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
Yes
  
Wind Resistant
No
  
No
  
Acid Resistant
Yes
  
No
  
Appearance
Dull and Soft
  
Rough and Shiny
  
Architecture
  
  
Interior Uses
Floor Tiles, Homes, Hotels, Kitchens
  
Decorative Aggregates, Interior Decoration
  
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration, Office Buildings
  
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
  
Other Architectural Uses
Curbing, Whetstones
  
Curbing
  
Industry
  
  
Construction Industry
Arrowheads, As Dimension Stone, Cobblestones, Cutting Tool, Rail Track Ballast, Roadstone
  
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
An Oil and Gas Reservoir, Commemorative Tablets, Creating Artwork, Used in aquariums
  
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
  
Types
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
  
Not Available
  
Features
Has High structural resistance against erosion and climate, Very fine grained rock
  
Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest rock
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Easter Island in the Polynesian Triangle, Pacific Ocean, Gateway of India in Mumbai, India, Gol Gumbaz in Karnataka, India
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Basalt forms when lava reaches the Earth's surface near an active volcano. The temperature of lava is between 1100 to 1250° C when it gets to the surface.
  
Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. It can be formed in two ways.
  
Composition
  
  
Mineral Content
Olivine, Plagioclase, Pyroxene
  
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
  
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Ca, CaO, Fe, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Contact Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Available
  
Coastal Erosion, Glacier Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
6
  
3.5-4
  
Grain Size
Fine Grained
  
Coarse Grained
  
Fracture
Conchoidal
  
Irregular
  
Streak
White to Grey
  
White
  
Porosity
Less Porous
  
Less Porous
  
Luster
Not Available
  
Shiny
  
Compressive Strength
37.40 N/mm2
  
28
107.55 N/mm2
  
19
Cleavage
Not Available
  
Imperfect
  
Toughness
2.3
  
2.1
  
Specific Gravity
2.8-3
  
3-3.01
  
Transparency
Opaque
  
Translucent to Opaque
  
Density
2.9-3.1 g/cm3
  
2.84-2.85 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.84 kJ/Kg K
  
15
1.25 kJ/Kg K
  
6
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
India, Russia
  
China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey
  
Africa
South Africa
  
Morocco, South Africa
  
Europe
Iceland
  
Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland, Venezuela
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Brazil
  
Argentina, Brazil, Colombia, Ecuador, Venezuela
  
Deposits in Oceania Continent
  
  
Australia
Not Yet Found
  
New Zealand, Western Australia