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Obsidian and Dunite


Dunite and Obsidian


Definition

Definition
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth   
Dunite is a green to brownish coarse-grained igneous rock mainly consisting of olivine   

History
  
  

Origin
Ethiopia   
New Zealand   

Discoverer
Obsius   
Ferdinand von Hochstetter   

Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius   
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
Opaque Rock   
Coarse Grained Rock, Opaque Rock   

Texture

Texture
Glassy   
Phaneritic   

Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow   
Dark Greenish - Grey   

Maintenance
Less   
Less   

Durability
Durable   
Durable   

Water Resistant
Yes   
Yes   

Scratch Resistant
Yes   
Yes   

Stain Resistant
No   
Yes   

Wind Resistant
No   
No   

Acid Resistant
No   
No   

Appearance
Shiny   
Rough and Shiny   

Uses

Architecture
  
  

Interior Uses
Decorative Aggregates, Interior Decoration   
Decorative Aggregates, Interior Decoration   

Exterior Uses
Garden Decoration   
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone   

Other Architectural Uses
Not Yet Used   
Curbing   

Industry
  
  

Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points   
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar   

Medical Industry
Surgery   
Not Yet Used   

Antiquity Uses
Artifacts, Jewellery   
Artifacts, Monuments, Sculpture, Small Figurines   

Other Uses
  
  

Commercial Uses
Creating Artwork, Mirror, Used in aquariums   
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds   

Types

Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian   
Not Available   

Features
Blocks negativity, Helps to protect against depression   
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
Not Yet Used   
Used   

Famous Monuments
Not Applicable   
Data Not Available   

Sculpture
Not Yet Used   
Used   

Famous Sculptures
Not Applicable   
Data Not Available   

Pictographs
Used   
Used   

Petroglyphs
Used   
Used   

Figurines
Not Yet Used   
Used   

Fossils
Absent   
Absent   

Formation

Formation
When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.   
Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. It can be formed in two ways.   

Composition
  
  

Mineral Content
Not Available   
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
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism   
Burial Metamorphism, Cataclastic Metamorphism, Contact 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
Chemical Erosion, Coastal Erosion, Glacier Erosion   
Coastal Erosion, Glacier Erosion, Water Erosion   

Properties

Physical Properties
  
  

Hardness
5-5.5   
3.5-4   

Grain Size
Not Applicable   
Coarse Grained   

Fracture
Conchoidal   
Irregular   

Streak
White   
White   

Porosity
Very Less Porous   
Less Porous   

Luster
Vitreous   
Shiny   

Compressive Strength
0.15 N/mm2   
33
107.55 N/mm2   
19

Cleavage
Non-Existent   
Imperfect   

Toughness
Not Available   
2.1   

Specific Gravity
2.6-2.7   
3-3.01   

Transparency
Translucent   
Translucent to Opaque   

Density
2.6 g/cm3   
2.84-2.85 g/cm3   

Thermal Properties
  
  

Specific Heat Capacity
0.92 kJ/Kg K   
10
1.25 kJ/Kg K   
6

Resistance
Heat Resistant, Impact Resistant   
Heat Resistant, Pressure Resistant, Wear Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
Afghanistan, Indonesia, Japan, Russia   
China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey   

Africa
Kenya   
Morocco, South Africa   

Europe
Greece, Hungary, Iceland, Italy, Turkey   
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, Mexico, USA   
Canada, USA   

South America
Argentina, Chile, Ecuador, Peru   
Argentina, Brazil, Colombia, Ecuador, Venezuela   

Deposits in Oceania Continent
  
  

Australia
New Zealand   
New Zealand, Western Australia   

Summary >>
<< Reserves

All about Obsidian and Dunite Properties

Know all about Obsidian and Dunite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Dunite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Dunite is Phaneritic. Obsidian appears Shiny and Dunite appears Rough and Shiny. The luster of Obsidian is vitreous while that of Dunite is shiny. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Dunite is available in dark greenish - grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Dunite are creating artwork, gemstone, jewelry, source of chromite, platinum, nickel and garnet, source of diamonds.

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