Adakite

Picrite

Adakite and Picrite

Adakite

Picrite

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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

History

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

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Rough and Shiny

Uses

Architecture

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

Industry

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.

Medical Industry

Antiquity Uses

Monuments, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

Other Uses

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

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

Aluminium Oxide, MgO, Silicon Dioxide

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Sea Erosion, Water Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

3-46.8

1 7

👆🏻

Grain Size

Fine to Medium Grained

Fine Grained

Fracture

Conchoidal

Uneven

Streak

Bluish Black

White, Greenish White or Grey

Porosity

Less Porous

Luster

Grainy, Pearly and Vitreous

Subvitreous to Dull

Compressive Strength

200.00 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.1

Specific Gravity

-99992.75-2.92

0 8.4

👆🏻

Transparency

Opaque

Density

-9999 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Africa

Ethiopia, Somalia, South Africa

South Africa

Europe

Iceland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

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).