Pseudotachylite

Tuff

Pseudotachylite and Tuff

Pseudotachylite

Tuff

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Definition

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

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

History

Origin

USA

Italy

Discoverer

Unknown

Etymology

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

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Quench

Clastic, Pyroclastic

Color

Black, Brown, Green, Grey, Pink, White

Brown, Grey, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Dull, Vesicular and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Building houses or walls, Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Gemstone

Creating Artwork

Types

Cataclastic rock

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

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.

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

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Calcite, Chlorite

Compound Content

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

Hydrogen Sulfide, Sulfur Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic 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, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

74-6

1 7

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Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven

Streak

Light to dark brown

White

Porosity

Less Porous

Highly Porous

Luster

Vitreous

Vitreous to Dull

Compressive Strength

60.00 N/mm²243.80 N/mm²

0.15 450

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Cleavage

Toughness

Specific Gravity

2.46-2.862.73

0 8.4

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Transparency

Transparent to Translucent

Opaque

Density

2.7-2.9 g/cm³1-1.8 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.92 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

South Korea

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

Western Africa

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

Europe

Great Britain, Switzerland

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

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Pseudotachylite and Tuff Properties

Know all about Pseudotachylite and Tuff properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Tuff belongs to Igneous Rocks.Texture of Pseudotachylite is Quench whereas that of Tuff is Clastic, Pyroclastic. Pseudotachylite appears Dull and Soft and Tuff appears Dull, Vesicular and Foilated. The luster of Pseudotachylite is vitreous while that of Tuff is vitreous to dull. Pseudotachylite is available in black, brown, green, grey, pink, white colors whereas Tuff is available in brown, grey, yellow colors. The commercial uses of Pseudotachylite and Tuff are creating artwork, gemstone.