Tuff

Hornfels

Tuff and Hornfels

Tuff

Hornfels

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Definition

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

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock

History

Origin

Italy

New Zealand

Discoverer

Unknown

Etymology

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

From German which means hornstone

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic, Pyroclastic

Granular, Platy

Color

Brown, Grey, Yellow

Brown, Dark Greenish - Grey, Green, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Vesicular and Foilated

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Decorative Aggregates, 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

Building houses or walls, Construction Aggregate

for Road Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

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

Biotite hornfels

Features

Always found as volcanic pipes over deep continental crust

Smooth to touch

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. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

Calcite, Chlorite

Andalusite

Compound Content

Hydrogen Sulfide, Sulfur Dioxide

Fe, Mg

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

Biological Weathering

Erosion

✔ ✘

Types of Erosion

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

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

Properties

Physical Properties

Hardness

4-62-3

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Uneven

Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Vitreous to Dull

Shiny

Compressive Strength

243.80 N/mm²5.80 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.733.4-3.9

0 8.4

👆🏻

Transparency

Opaque

Density

1-1.8 g/cm³0.25-0.30 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.20 kJ/Kg K0.84 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

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand

Africa

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

Cameroon, East Africa, Tanzania, 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

Canada, USA

South America

Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay

Bolivia, Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New South Wales, New Zealand, Queensland, Western Australia

All about Tuff and Hornfels Properties

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