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Websterite and Obsidian


Obsidian and Websterite


Definition

Definition
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.   
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   

History
  
  

Origin
Webster, North Carolina   
Ethiopia   

Discoverer
Unknown   
Obsius   

Etymology
From the town of Webster located in North Carolina   
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius   

Class
Igneous Rocks   
Igneous Rocks   

Sub-Class
Durable Rock, Hard Rock   
Durable Rock, Medium Hardness Rock   

Family
  
  

Group
Plutonic   
Volcanic   

Other Categories
Coarse Grained Rock, Opaque Rock   
Opaque Rock   

Texture

Texture
Clastic, Granular, Phaneritic, Porphyritic   
Glassy   

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

Maintenance
Less   
Less   

Durability
Durable   
Durable   

Water Resistant
Yes   
Yes   

Scratch Resistant
Yes   
Yes   

Stain Resistant
Yes   
No   

Wind Resistant
Yes   
No   

Acid Resistant
Yes   
No   

Appearance
Layered, Banded, Veined and Shiny   
Shiny   

Uses

Architecture
  
  

Interior Uses
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration   
Decorative Aggregates, Interior Decoration   

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

Other Architectural Uses
Curbing   
Not Yet Used   

Industry
  
  

Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate   
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points   

Medical Industry
Not Yet Used   
Surgery   

Antiquity Uses
Artifacts   
Artifacts, Jewellery   

Other Uses
  
  

Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones   
Creating Artwork, Mirror, Used in aquariums   

Types

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

Features
Generally rough to touch, Is one of the oldest rock   
Blocks negativity, Helps to protect against depression   

Archaeological Significance
  
  

Monuments
Not Yet Used   
Not Yet Used   

Famous Monuments
Data Not Available   
Not Applicable   

Sculpture
Not Yet Used   
Not Yet Used   

Famous Sculptures
Data Not Available   
Not Applicable   

Pictographs
Not Used   
Used   

Petroglyphs
Not Used   
Used   

Figurines
Not Yet Used   
Not Yet Used   

Fossils
Absent   
Absent   

Formation

Formation
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.   
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.   

Composition
  
  

Mineral Content
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene   
Not Available   

Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide   
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide   

Transformation
  
  

Metamorphism
Yes   
Yes   

Types of Metamorphism
Burial Metamorphism, Impact 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, Water Erosion, Wind Erosion   
Chemical Erosion, Coastal Erosion, Glacier Erosion   

Properties

Physical Properties
  
  

Hardness
7   
5-5.5   

Grain Size
Coarse Grained   
Not Applicable   

Fracture
Uneven   
Conchoidal   

Streak
White, Greenish White or Grey   
White   

Porosity
Less Porous   
Very Less Porous   

Luster
Dull to Vitreous to Submetallic   
Vitreous   

Compressive Strength
Not Available   
0.15 N/mm2   
33

Cleavage
Irregular   
Non-Existent   

Toughness
Not Available   
Not Available   

Specific Gravity
3.2-3.5   
2.6-2.7   

Transparency
Opaque   
Translucent   

Density
3.1-3.6 g/cm3   
2.6 g/cm3   

Thermal Properties
  
  

Specific Heat Capacity
Not Available   
0.92 kJ/Kg K   
10

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

Reserves

Deposits in Eastern Continents
  
  

Asia
India, Russia   
Afghanistan, Indonesia, Japan, Russia   

Africa
South Africa   
Kenya   

Europe
Germany, Greece, Italy, Scotland, Turkey   
Greece, Hungary, Iceland, Italy, Turkey   

Others
Greenland   
Not Yet Found   

Deposits in Western Continents
  
  

North America
Canada, USA   
Canada, Mexico, USA   

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

Deposits in Oceania Continent
  
  

Australia
New Zealand, Queensland   
New Zealand   

Summary >>
<< Reserves

All about Websterite and Obsidian Properties

Know all about Websterite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Websterite and Obsidian belong to Igneous Rocks.Texture of Websterite is Clastic, Granular, Phaneritic, Porphyritic whereas that of Obsidian is Glassy. Websterite appears Layered, Banded, Veined and Shiny and Obsidian appears Shiny. The luster of Websterite is dull to vitreous to submetallic while that of Obsidian is vitreous. Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Websterite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones and that of Obsidian are creating artwork, mirror, used in aquariums.

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