Adakite

Tephrite

Adakite and Tephrite

Adakite

Tephrite

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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

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

History

Origin

Adak, Aleutian Islands

Germany

Discoverer

Defant and Drummond

Van Tooren

Etymology

From Adak, Aleutian Islands

From Greek tephra, ashes from Indo-European base, to burn

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

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Porphyritic

Aphanitic to Porphyritic

Color

Black, Brown, Light to Dark Grey

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Whetstones

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Landscaping

Medical Industry

Antiquity Uses

Monuments, Sculpture, Small Figurines

Artifacts, Sculpture

Other Uses

Commercial Uses

Commemorative Tablets, Pottery, Used in aquariums

Production of Lime, Soil Conditioner

Types

Intermediate volcanic rock

Igneous rock

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.

Tephrite 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

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Compound Content

Aluminium Oxide, MgO, Silicon Dioxide

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Sea Erosion, Water Erosion

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

Properties

Physical Properties

Hardness

3-46.5

1 7

👆🏻

Grain Size

Fine to Medium Grained

Medium to Fine Coarse Grained

Fracture

Conchoidal

Uneven

Streak

Bluish Black

Porosity

Less Porous

Very Less Porous

Luster

Grainy, Pearly and Vitreous

Subvitreous to Dull

Compressive Strength

200.00 N/mm²90.00 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Toughness

2.4

Specific Gravity

-99992.86

0 8.4

👆🏻

Transparency

Opaque

Density

-9999 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Africa

Ethiopia, Somalia, South Africa

Namibia, Uganda

Europe

Iceland

Germany, Hungary, Italy, Portugal, Spain

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Brazil

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

All about Adakite and Tephrite Properties

Know all about Adakite and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Adakite and Tephrite belong to Igneous Rocks.Texture of Adakite is Porphyritic whereas that of Tephrite is Aphanitic to Porphyritic. Adakite appears Dull and Soft and Tephrite appears Vesicular. The luster of Adakite is grainy, pearly and vitreous while that of Tephrite is subvitreous to dull. Adakite is available in black, brown, light to dark grey colors whereas Tephrite is available in black, brown, green, grey, white colors. The commercial uses of Adakite are commemorative tablets, pottery, used in aquariums and that of Tephrite are production of lime, soil conditioner.