Picrite and Adakite
Definition
Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
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
History
Origin
Hawaii Islands
Adak, Aleutian Islands
Discoverer
Unknown
Defant and Drummond
Etymology
From Greek pikros bitter + -ite, 19th century
From Adak, Aleutian Islands
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Texture
Earthy, Rough
Porphyritic
Color
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
Black, Brown, Light to Dark Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
Yes
No
Wind Resistant
Yes
Yes
Acid Resistant
Yes
Yes
Appearance
Rough and Shiny
Dull and Soft
Uses
Architecture
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Curbing
Whetstones
Industry
Construction Industry
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Commemorative Tablets, Pottery, Used in aquariums
Types
Types
Oceanite
Not Available
Features
Host Rock for Lead
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Used
Fossils
Absent
Absent
Formation
Formation
Picrite 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.
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.
Composition
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Olivine, Plagioclase, Pyroxene
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Aluminium Oxide, MgO, Silicon Dioxide
Transformation
Metamorphism
Yes
Yes
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering
Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Properties
Physical Properties
Hardness
6.8
3-4
Grain Size
Fine Grained
Fine to Medium Grained
Fracture
Uneven
Conchoidal
Streak
White, Greenish White or Grey
Bluish Black
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Grainy, Pearly and Vitreous
Compressive Strength
189.00 N/mm2
11
Not Available
Cleavage
Imperfect
Not Available
Toughness
2.1
Not Available
Specific Gravity
2.75-2.92
Not Available
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
Not Available
Thermal Properties
Specific Heat Capacity
0.88 kJ/Kg K
13
Not Available
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
India, Russia
India, Russia
Africa
South Africa
Ethiopia, Somalia, South Africa
Europe
Iceland
Iceland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil
Deposits in Oceania Continent
Australia
Not Yet Found
Not Yet Found
All about Picrite and Adakite Properties
Know all about Picrite and Adakite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Adakite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Adakite is Porphyritic. Picrite appears Rough and Shiny and Adakite appears Dull and Soft. The luster of Picrite is subvitreous to dull while that of Adakite is grainy, pearly and vitreous. Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors whereas Adakite is available in black, brown, light to dark grey colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Adakite are commemorative tablets, pottery, used in aquariums.
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