Tuff

Metapelite

Tuff and Metapelite

Tuff

Metapelite

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Definition

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

Metapelite is an old and currently not widely used field geological term for a clay rich fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone

History

Origin

Italy

Discoverer

Unknown

Etymology

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

From Pelos or clay in Greek

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

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

Texture

Clastic, Pyroclastic

Foliated

Color

Brown, Grey, Yellow

Dark Greenish - Grey, Green, Light Green, Light Greenish Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Vesicular and Foilated

Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Building houses or walls, Construction Aggregate

Cement Manufacture, Construction Aggregate, for Road Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts

Other Uses

Commercial Uses

Creating Artwork

Commemorative Tablets, Creating Artwork

Types

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

Metamorphic rock

Features

Always found as volcanic pipes over deep continental crust

Easily splits into thin plates, It is One of the Oldest, Strongest and Hardest Rock

Archaeological Significance

Monuments

Famous Monuments

Easter Island in the Polynesian Triangle, Pacific Ocean

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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

Composition

Mineral Content

Calcite, Chlorite

Albite, Chlorite, Quartz

Compound Content

Hydrogen Sulfide, Sulfur Dioxide

Aluminium Oxide, CaO, MgO

Transformation

Metamorphism

✔ ✘

Types of 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, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

4-65-6

1 7

👆🏻

Grain Size

Fine Grained

Medium to Fine Coarse Grained

Fracture

Uneven

Fibrous

Streak

White

Porosity

Highly Porous

Luster

Vitreous to Dull

Earthy

Compressive Strength

243.80 N/mm²40.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.733.4-3.7

0 8.4

👆🏻

Transparency

Opaque

Density

1-1.8 g/cm³0-300 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.20 kJ/Kg K0.72 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

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

Western Africa

Europe

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

United Kingdom

Others

Antarctica, Hawaii Islands

Deposits in Western Continents

North America

Canada, Costa Rica, Panama, USA

South America

Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay

Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Tuff and Metapelite Properties

Know all about Tuff and Metapelite properties here. All properties of rocks are important as they define the type of rock and its application. Tuff belongs to Igneous Rocks while Metapelite belongs to Metamorphic Rocks.Texture of Tuff is Clastic, Pyroclastic whereas that of Metapelite is Foliated. Tuff appears Dull, Vesicular and Foilated and Metapelite appears Banded. The luster of Tuff is vitreous to dull while that of Metapelite is earthy. Tuff is available in brown, grey, yellow colors whereas Metapelite is available in dark greenish - grey, green, light green, light greenish grey colors. The commercial uses of Tuff are creating artwork and that of Metapelite are commemorative tablets, creating artwork.