Picrite

Adakite

Picrite and Adakite

Picrite

Adakite

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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

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Earthy, Rough

Porphyritic

Color

Black, Brown, Green, Grey, Pink, White, Yellow

Black, Brown, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

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

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

Oceanite

Intermediate volcanic rock

Features

Host Rock for Lead

Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

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

6.83-4

1 7

👆🏻

Grain Size

Fine Grained

Fine to Medium Grained

Fracture

Uneven

Conchoidal

Streak

White, Greenish White or Grey

Bluish Black

Porosity

Less Porous

Luster

Subvitreous to Dull

Grainy, Pearly and Vitreous

Compressive Strength

189.00 N/mm²200.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.1

Specific Gravity

2.75-2.92-9999

0 8.4

👆🏻

Transparency

Opaque

Density

1.5-2.5 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Africa

South Africa

Ethiopia, Somalia, South Africa

Europe

Iceland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

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, 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.