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
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Origin
Adak, Aleutian Islands
Hawaii Islands
Discoverer
Defant and Drummond
Unknown
Etymology
From Adak, Aleutian Islands
From Greek pikros bitter + -ite, 19th century
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Earthy, Rough
Color
Black, Brown, Light to Dark Grey
Black, Brown, Green, Grey, Pink, White, Yellow
Durability
Durable
Durable
Appearance
Dull and Soft
Rough and Shiny
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Whetstones
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
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.
Antiquity Uses
Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Commemorative Tablets, Pottery, Used in aquariums
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Types
Intermediate volcanic rock
Oceanite
Features
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Host Rock for Lead
Archaeological Significance
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.
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.
Mineral Content
Olivine, Plagioclase, Pyroxene
Biotite, Olivine, Plagioclase, Pyrrhotite
Compound Content
Aluminium Oxide, MgO, Silicon Dioxide
Al, CaO, Carbon Dioxide, Mg, MgO
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Chemical Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine to Medium Grained
Fine Grained
Fracture
Conchoidal
Uneven
Streak
Bluish Black
White, Greenish White or Grey
Porosity
Less Porous
Less Porous
Luster
Grainy, Pearly and Vitreous
Subvitreous to Dull
Specific Gravity
-9999
2.75-2.92
Transparency
Opaque
Opaque
Density
-9999 g/cm3
1.5-2.5 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
India, Russia
India, Russia
Africa
Ethiopia, Somalia, South Africa
South Africa
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil
Deposits in Oceania Continent
All about Adakite and Picrite Properties
Know all about Adakite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Adakite and Picrite belong to Igneous Rocks.Texture of Adakite is Porphyritic whereas that of Picrite is Earthy, Rough. Adakite appears Dull and Soft and Picrite appears Rough and Shiny. The luster of Adakite is grainy, pearly and vitreous while that of Picrite is subvitreous to dull. Adakite is available in black, brown, light to dark grey colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Adakite are commemorative tablets, pottery, used in aquariums and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).