Gossan

Tuff

Gossan and Tuff

Gossan

Tuff

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Definition

Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.

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

History

Origin

Indonesia

Italy

Discoverer

Cornish Gossen

Unknown

Etymology

From Cornish gossen from gos, blood from Old Cornish guit

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Rough, Sandy

Clastic, Pyroclastic

Color

Brown, Brown- Black, Gold, Green, Rust

Brown, Grey, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Banded

Dull, Vesicular and Foilated

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate

Building houses or walls, Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Gemstone

Creating Artwork

Types

Translocated gossan and Leakage gossan

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

Features

Clasts are smooth to touch, Easily splits into thin plates

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

Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.

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

Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon

Calcite, Chlorite

Compound Content

Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur

Hydrogen Sulfide, Sulfur 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, Sea Erosion, Wind Erosion

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

Properties

Physical Properties

Hardness

4-54-6

1 7

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Grain Size

Fine to Medium Grained

Fine Grained

Fracture

Conchoidal

Uneven

Streak

White to Grey

White

Porosity

Highly Porous

Luster

Metallic

Vitreous to Dull

Compressive Strength

-243.80 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.02.73

0 8.4

👆🏻

Transparency

Opaque

Density

-9999 g/cm³1-1.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.24 kJ/Kg K0.20 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Indonesia, Russia, Singapore, 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

Cape Verde, Ethiopia, Ghana, South Africa, Western Africa

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

Europe

Albania, France, Germany, Great Britain, United Kingdom

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

Others

Antarctica, Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

Canada, Costa Rica, Panama, USA

South America

Brazil, Colombia, Ecuador

Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

New South Wales, South Australia, Western Australia

Central Australia, Western Australia

All about Gossan and Tuff Properties

Know all about Gossan and Tuff properties here. All properties of rocks are important as they define the type of rock and its application. Gossan belongs to Metamorphic Rocks while Tuff belongs to Igneous Rocks.Texture of Gossan is Rough, Sandy whereas that of Tuff is Clastic, Pyroclastic. Gossan appears Dull and Banded and Tuff appears Dull, Vesicular and Foilated. The luster of Gossan is metallic while that of Tuff is vitreous to dull. Gossan is available in brown, brown- black, gold, green, rust colors whereas Tuff is available in brown, grey, yellow colors. The commercial uses of Gossan are cemetery markers, commemorative tablets, gemstone and that of Tuff are creating artwork.