Nephelinite

Adakite

Nephelinite and Adakite

Nephelinite

Adakite

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Definition

Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).

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

Brazil

Adak, Aleutian Islands

Discoverer

Unknown

Defant and Drummond

Etymology

from French néphéline, from Greek nephelē

From Adak, Aleutian Islands

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Aphanitic

Porphyritic

Color

Black, Brown, Green, Grey, White

Black, Brown, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Skeletal

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens

Exterior Uses

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

As Building Stone, As Facing Stone, Office Buildings

Other Architectural Uses

Curbing

Whetstones

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)

Commemorative Tablets, Pottery, Used in aquariums

Types

Peralkaline Nephelinite

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

Nephelinite 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

Clinopyroxene, Nepheline, Plagioclase

Olivine, Plagioclase, Pyroxene

Compound Content

Ca, CaO, Carbon, Cl, MgO

Aluminium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

Coastal Erosion, Sea Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.53-4

1 7

👆🏻

Grain Size

Fine Grained

Fine to Medium Grained

Fracture

Flat

Conchoidal

Streak

White

Bluish Black

Porosity

Less Porous

Luster

Vitreous to Metallic

Grainy, Pearly and Vitreous

Compressive Strength

35.00 N/mm²200.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.7

Specific Gravity

2.4-2.9-9999

0 8.4

👆🏻

Transparency

Opaque

Density

2.5-3 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

Japan

India, Russia

Africa

Rwanda, Tanzania

Ethiopia, Somalia, South Africa

Europe

Iceland

Others

Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

South America

Colombia

Brazil

Deposits in Oceania Continent

Australia

All about Nephelinite and Adakite Properties

Know all about Nephelinite and Adakite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Adakite belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Adakite is Porphyritic. Nephelinite appears Skeletal and Adakite appears Dull and Soft. The luster of Nephelinite is vitreous to metallic while that of Adakite is grainy, pearly and vitreous. Nephelinite is available in black, brown, green, grey, white colors whereas Adakite is available in black, brown, light to dark grey colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Adakite are commemorative tablets, pottery, used in aquariums.