Obsidian and Andesite
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
Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava
History
Origin
Ethiopia
North America
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Andes mountains, where it is found in abundance
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Volcanic
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Glassy
Aphanitic to Porphyritic
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Bluish - Grey, Grey, Pink, Yellow
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
Yes
Stain Resistant
No
Yes
Wind Resistant
No
No
Acid Resistant
No
Yes
Appearance
Shiny
Dull and Soft
Uses
Architecture
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens
Exterior Uses
Garden Decoration
Office Buildings, Roof Tiles
Other Architectural Uses
Not Yet Used
Curbing
Industry
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Cobblestones, Construction Aggregate, for Road Aggregate
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
Commemorative Tablets, Creating Artwork
Types
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Icelandite
Features
Blocks negativity, Helps to protect against depression
Generally rough to touch, High silica content, Is one of the oldest rock
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Middle of the Earth in Ecuador
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.
Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.
Composition
Mineral Content
Not Available
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Silicon 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
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Properties
Physical Properties
Hardness
5-5.5
7
Grain Size
Not Applicable
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
White
White
Porosity
Very Less Porous
Less Porous
Luster
Vitreous
Vitreous
Compressive Strength
0.15 N/mm2
33
225.00 N/mm2
7
Cleavage
Non-Existent
Not Available
Toughness
Not Available
1.1
Specific Gravity
2.6-2.7
2.5-2.8
Transparency
Translucent
Opaque
Density
2.6 g/cm3
2.11-2.36 g/cm3
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K
10
2.39 kJ/Kg K
2
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
India, Indonesia, Japan, Nepal, South Korea
Africa
Kenya
Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania
Europe
Greece, Hungary, Iceland, Italy, Turkey
Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Mexico, USA
South America
Argentina, Chile, Ecuador, Peru
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand
New South Wales, New Zealand, Western Australia
All about Obsidian and Andesite Properties
Know all about Obsidian and Andesite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Andesite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Andesite is Aphanitic to Porphyritic. Obsidian appears Shiny and Andesite appears Dull and Soft. The luster of Obsidian and Andesite is vitreous. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Andesite is available in bluish - grey, grey, pink, yellow colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Andesite are commemorative tablets, creating artwork.
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