Obsidian and Norite
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
Norite is a mafic intrusive igneous rock composed largely of the calcium-rich plagioclase labradorite, orthopyroxene, and olivine
History
Origin
Ethiopia
Norway
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From the Norwegian name for Norway, Norge
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard 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 Grey to Black
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
No
Yes
Wind Resistant
No
Yes
Acid Resistant
No
Yes
Appearance
Shiny
Veined and Shiny
Uses
Architecture
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Not Yet Used
Curbing
Industry
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts, Jewellery
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Not Available
Features
Blocks negativity, Helps to protect against depression
Smooth to touch
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
Not Used
Petroglyphs
Used
Not 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.
Norite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Composition
Mineral Content
Not Available
Augite, Olivine, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Transformation
Metamorphism
Yes
Yes
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Cataclastic Metamorphism, Impact Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion
Properties
Physical Properties
Hardness
5-5.5
7
Grain Size
Not Applicable
Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White
Black
Porosity
Very Less Porous
Highly Porous
Luster
Vitreous
Not Available
Compressive Strength
0.15 N/mm2
33
225.00 N/mm2
7
Cleavage
Non-Existent
Not Available
Toughness
Not Available
1.6
Specific Gravity
2.6-2.7
2.86-2.87
Transparency
Translucent
Opaque
Density
2.6 g/cm3
2.7-3.3 g/cm3
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K
10
Not Available
Resistance
Heat Resistant, Impact Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
India, Russia
Africa
Kenya
South Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Germany, Greece, Italy, Scotland, Turkey
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New Zealand
New Zealand, Queensland
All about Obsidian and Norite Properties
Know all about Obsidian and Norite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Norite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Norite is Phaneritic. Obsidian appears Shiny and Norite appears Veined and Shiny. The luster of Obsidian is vitreous while that of Norite is not available. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Norite is available in dark grey to black colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Norite are cemetery markers, commemorative tablets, laboratory bench tops, jewelry, sea defence, tombstones.
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