Nephelinite

Tuff

Nephelinite and Tuff

Nephelinite

Tuff

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Definition

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

Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption

History

Origin

Brazil

Italy

Discoverer

Unknown

Etymology

from French néphéline, from Greek nephelē

From a Latin word tophous then in Italian tufo and finally tuff

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

Texture

Aphanitic

Clastic, Pyroclastic

Color

Black, Brown, Green, Grey, White

Brown, Grey, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Skeletal

Dull, Vesicular and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Exterior Uses

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Building houses or walls, Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

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

Creating Artwork

Types

Peralkaline Nephelinite

Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.

Features

Host Rock for Lead

Always found as volcanic pipes over deep continental crust

Archaeological Significance

Monuments

Famous Monuments

Easter Island in the Polynesian Triangle, Pacific Ocean

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.

Tuff is formed when large masses of ash and sand which are mixed with hot gases are ejected by a volcano and avalanche rapidly down its slopes.

Composition

Mineral Content

Clinopyroxene, Nepheline, Plagioclase

Calcite, Chlorite

Compound Content

Ca, CaO, Carbon, Cl, MgO

Hydrogen Sulfide, Sulfur Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

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

Properties

Physical Properties

Hardness

6.54-6

1 7

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Grain Size

Fine Grained

Fracture

Flat

Uneven

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Vitreous to Metallic

Vitreous to Dull

Compressive Strength

35.00 N/mm²243.80 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.7

Specific Gravity

2.4-2.92.73

0 8.4

👆🏻

Transparency

Opaque

Density

2.5-3 g/cm³1-1.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.20 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan

Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen

Africa

Rwanda, Tanzania

Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda

Europe

France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom

Others

Hawaii Islands

Antarctica, Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

Canada, Costa Rica, Panama, USA

South America

Colombia

Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Nephelinite and Tuff Properties

Know all about Nephelinite and Tuff properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Tuff belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Tuff is Clastic, Pyroclastic. Nephelinite appears Skeletal and Tuff appears Dull, Vesicular and Foilated. The luster of Nephelinite is vitreous to metallic while that of Tuff is vitreous to dull. Nephelinite is available in black, brown, green, grey, white colors whereas Tuff is available in brown, grey, yellow colors. The commercial uses of Nephelinite and Tuff are creating artwork, soil conditioner, source of magnesia (mgo).