Nephelinite

Pseudotachylite

Nephelinite and Pseudotachylite

Nephelinite

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Definition

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

Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.

History

Origin

Brazil

USA

Discoverer

Unknown

Etymology

from French néphéline, from Greek nephelē

From pseudo- +‎ tachylite, a glassy rock generated by frictional heat within faults.

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Aphanitic

Quench

Color

Black, Brown, Green, Grey, White

Black, Brown, Green, Grey, Pink, White

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, Entryways, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

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

Creating Artwork, Gemstone

Types

Peralkaline Nephelinite

Cataclastic rock

Features

Host Rock for Lead

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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

Clinopyroxene, Nepheline, Plagioclase

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Compound Content

Ca, CaO, Carbon, Cl, MgO

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.57

1 7

👆🏻

Grain Size

Fine Grained

Very fine-grained

Fracture

Flat

Uneven

Streak

White

Light to dark brown

Porosity

Less Porous

Luster

Vitreous to Metallic

Vitreous

Compressive Strength

35.00 N/mm²60.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.7

Specific Gravity

2.4-2.92.46-2.86

0 8.4

👆🏻

Transparency

Opaque

Transparent to Translucent

Density

2.5-3 g/cm³2.7-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan

South Korea

Africa

Rwanda, Tanzania

Western Africa

Europe

Great Britain, Switzerland

Others

Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

South America

Colombia

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Nephelinite and Pseudotachylite Properties

Know all about Nephelinite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Nephelinite is Aphanitic whereas that of Pseudotachylite is Quench. Nephelinite appears Skeletal and Pseudotachylite appears Dull and Soft. The luster of Nephelinite is vitreous to metallic while that of Pseudotachylite is vitreous. Nephelinite is available in black, brown, green, grey, white colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Pseudotachylite are creating artwork, gemstone.