Tuff

Chert

Tuff and Chert

Tuff

Chert

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Definition

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

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

History

Origin

Italy

Discoverer

Unknown

Etymology

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

From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic, Pyroclastic

Banded, Rough

Color

Brown, Grey, Yellow

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Vesicular and Foilated

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Building houses or walls, Construction Aggregate

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

Types

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

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

Features

Always found as volcanic pipes over deep continental crust

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Archaeological Significance

Monuments

Famous Monuments

Easter Island in the Polynesian Triangle, Pacific Ocean

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

Composition

Mineral Content

Calcite, Chlorite

Quartz, Silicon

Compound Content

Hydrogen Sulfide, Sulfur Dioxide

Silicon Dioxide

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

Properties

Physical Properties

Hardness

4-66.5-7

1 7

👆🏻

Grain Size

Fine Grained

Very fine-grained

Fracture

Uneven

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Vitreous to Dull

Waxy and Dull

Compressive Strength

243.80 N/mm²450.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.5

Specific Gravity

2.732.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

1-1.8 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.20 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear 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

China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

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

Kenya, Morocco, South Africa, Tanzania

Europe

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

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Antarctica, Hawaii Islands

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Costa Rica, Panama, USA

Canada, Mexico, USA

South America

Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay

Bolivia, Brazil

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New South Wales, Queensland, South Australia, Western Australia

All about Tuff and Chert Properties

Know all about Tuff and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Tuff belongs to Igneous Rocks while Chert belongs to Sedimentary Rocks.Texture of Tuff is Clastic, Pyroclastic whereas that of Chert is Banded, Rough. Tuff appears Dull, Vesicular and Foilated and Chert appears Glassy or Pearly. The luster of Tuff is vitreous to dull while that of Chert is waxy and dull. Tuff is available in brown, grey, yellow colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Tuff are creating artwork and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.