Gossan

Skarn

Gossan and Skarn

Gossan

Skarn

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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.

Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin

History

Origin

Indonesia

USA, Australia

Discoverer

Cornish Gossen

Tornebohm

Etymology

From Cornish gossen from gos, blood from Old Cornish guit

From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.

Class

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Rough, Sandy

Earthy, Mud-rich, Rough

Color

Brown, Brown- Black, Gold, Green, Rust

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Banded

Dull

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Gemstone

Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)

Types

Translocated gossan and Leakage gossan

Endoskarns

Features

Clasts are smooth to touch, Easily splits into thin plates

Host Rock for Lead, Zinc and Copper Deposits

Archaeological Significance

Monuments

Famous Monuments

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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

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

Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite

Compound Content

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

Au, CaO, Carbon Dioxide, Cu, Fe, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Properties

Physical Properties

Hardness

4-56.5

1 7

👆🏻

Grain Size

Fine to Medium Grained

Fine Grained

Fracture

Conchoidal

Irregular

Streak

White to Grey

Light to dark brown

Porosity

Highly Porous

Less Porous

Luster

Metallic

Waxy and Dull

Compressive Strength

-70.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.4

Specific Gravity

2.02.86

0 8.4

👆🏻

Transparency

Opaque

Density

-9999 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.24 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Indonesia, Russia, Singapore, South Korea

China, India, Russia, Saudi Arabia, South Korea, Sri Lanka

Africa

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

South Africa, Western Africa

Europe

Albania, France, Germany, Great Britain, United Kingdom

United Kingdom

Others

Deposits in Western Continents

North America

Canada, USA

Canada

South America

Brazil, Colombia, Ecuador

Brazil, Colombia, Paraguay

Deposits in Oceania Continent

Australia

New South Wales, South Australia, Western Australia

Central Australia, Western Australia

All about Gossan and Skarn Properties

Know all about Gossan and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Gossan and Skarn belong to Metamorphic Rocks.Texture of Gossan is Rough, Sandy whereas that of Skarn is Earthy, Mud-rich, Rough. Gossan appears Dull and Banded and Skarn appears Dull. The luster of Gossan is metallic while that of Skarn is waxy and dull. Gossan is available in brown, brown- black, gold, green, rust colors whereas Skarn is available in black, brown, green, grey, white colors. The commercial uses of Gossan are cemetery markers, commemorative tablets, gemstone and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).