Tuff

Coquina

Tuff and Coquina

Tuff

Coquina

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Definition

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

Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically-sorted fragments of the shells of molluscs, trilobites, brachiopods, or other invertebrates

History

Origin

Italy

European Foreland Basins

Discoverer

Unknown

Etymology

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

From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Clastic, Pyroclastic

Clastic

Color

Brown, Grey, Yellow

Beige, Buff, Orange

Maintenance

Durability

Durable

Non-Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Vesicular and Foilated

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Decorative Aggregates, Homes, Hotels, Interior Decoration

Exterior Uses

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

Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

Building houses or walls, Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork

Types

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

Sedimentary rock

Features

Always found as volcanic pipes over deep continental crust

Available in Lots of Colors and Patterns, Is one of the oldest rock

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.

Coquina is a sedimentary rock which is formed when billions of small clam-like seashell, called Coquina, or cockleshell are die and hence are deposited, buried and turns into a rock when pressure is applied.

Composition

Mineral Content

Calcite, Chlorite

Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite

Compound Content

Hydrogen Sulfide, Sulfur Dioxide

CaO, Carbon Dioxide, Iron(III) Oxide, 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

Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

4-61-2

1 7

👆🏻

Grain Size

Fine Grained

Coarse Grained

Fracture

Uneven

Irregular

Streak

White

Porosity

Highly Porous

Luster

Vitreous to Dull

Dull to Vitreous to Submetallic

Compressive Strength

243.80 N/mm²-

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.731.10-2.24

0 8.4

👆🏻

Transparency

Opaque

Density

1-1.8 g/cm³2.8-2.9 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

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

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

USA

South America

Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Tuff and Coquina Properties

Know all about Tuff and Coquina properties here. All properties of rocks are important as they define the type of rock and its application. Tuff belongs to Igneous Rocks while Coquina belongs to Sedimentary Rocks.Texture of Tuff is Clastic, Pyroclastic whereas that of Coquina is Clastic. Tuff appears Dull, Vesicular and Foilated and Coquina appears Layered, Banded, Veined and Shiny. The luster of Tuff is vitreous to dull while that of Coquina is dull to vitreous to submetallic. Tuff is available in brown, grey, yellow colors whereas Coquina is available in beige, buff, orange colors. The commercial uses of Tuff and Coquina are creating artwork.