Adakite and Obsidian
Definition
Definition
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
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
Adak, Aleutian Islands
Ethiopia
Discoverer
Defant and Drummond
Obsius
Etymology
From Adak, Aleutian Islands
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Opaque Rock
Texture
Texture
Porphyritic
Glassy
Color
Black, Brown, Light to Dark Grey
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
No
Yes
Scratch Resistant
No
Yes
Stain Resistant
No
No
Wind Resistant
Yes
No
Acid Resistant
Yes
No
Appearance
Dull and Soft
Shiny
Uses
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
Garden Decoration
Other Architectural Uses
Whetstones
Not Yet Used
Industry
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Not Yet Used
Surgery
Antiquity Uses
Monuments, Sculpture, Small Figurines
Artifacts, Jewellery
Other Uses
Commercial Uses
Commemorative Tablets, Pottery, Used in aquariums
Creating Artwork, Mirror, Used in aquariums
Types
Types
Not Available
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Used
Petroglyphs
Used
Used
Figurines
Used
Not Yet Used
Fossils
Absent
Absent
Formation
Formation
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
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
Olivine, Plagioclase, Pyroxene
Not Available
Compound Content
Aluminium Oxide, MgO, Silicon Dioxide
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
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Weathering
Yes
Yes
Types of Weathering
Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Properties
Physical Properties
Hardness
3-4
5-5.5
Grain Size
Fine to Medium Grained
Not Applicable
Fracture
Conchoidal
Conchoidal
Streak
Bluish Black
White
Porosity
Less Porous
Very Less Porous
Luster
Grainy, Pearly and Vitreous
Vitreous
Compressive Strength
Not Available
0.15 N/mm2
33
Cleavage
Not Available
Non-Existent
Toughness
Not Available
Not Available
Specific Gravity
Not Available
2.6-2.7
Transparency
Opaque
Translucent
Density
Not Available
2.6 g/cm3
Thermal Properties
Specific Heat Capacity
Not Available
0.92 kJ/Kg K
10
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Reserves
Deposits in Eastern Continents
Asia
India, Russia
Afghanistan, Indonesia, Japan, Russia
Africa
Ethiopia, Somalia, South Africa
Kenya
Europe
Iceland
Greece, Hungary, Iceland, Italy, Turkey
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand
All about Adakite and Obsidian Properties
Know all about Adakite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Adakite and Obsidian belong to Igneous Rocks.Texture of Adakite is Porphyritic whereas that of Obsidian is Glassy. Adakite appears Dull and Soft and Obsidian appears Shiny. The luster of Adakite is grainy, pearly and vitreous while that of Obsidian is vitreous. Adakite is available in black, brown, light to dark grey colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Adakite are commemorative tablets, pottery, used in aquariums and that of Obsidian are creating artwork, mirror, used in aquariums.
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