Gossan

Gneiss

Gossan and Gneiss

Gossan

Gneiss

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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.

Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks

History

Origin

Indonesia

Discoverer

Cornish Gossen

Unknown

Etymology

From Cornish gossen from gos, blood from Old Cornish guit

From the Middle High German verb gneist (to spark; so called because the rock glitters)

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

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Rough, Sandy

Banded, Foliated, Platy

Color

Brown, Brown- Black, Gold, Green, Rust

Black, Brown, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Banded

Foliated

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, Flooring, 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 Dimension Stone

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Gemstone

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

Types

Translocated gossan and Leakage gossan

Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.

Features

Clasts are smooth to touch, Easily splits into thin plates

Generally rough to touch, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Konark Sun Temple in India, Washington Monument, US

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.

Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.

Composition

Mineral Content

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

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

Compound Content

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

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Impact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Properties

Physical Properties

Hardness

4-57

1 7

👆🏻

Grain Size

Fine to Medium Grained

Medium to Coarse Grained

Fracture

Conchoidal

Irregular

Streak

White to Grey

White

Porosity

Highly Porous

Very Less Porous

Luster

Metallic

Dull

Compressive Strength

-125.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.2

Specific Gravity

2.02.5-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

-9999 g/cm³2.6-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.24 kJ/Kg K0.70 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia

Africa

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

Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo

Europe

Albania, France, Germany, Great Britain, United Kingdom

Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom

Others

Deposits in Western Continents

North America

Canada, USA

Canada, Costa Rica, Cuba, Mexico, Panama, USA

South America

Brazil, Colombia, Ecuador

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, South Australia, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Gossan and Gneiss Properties

Know all about Gossan and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Gossan and Gneiss belong to Metamorphic Rocks.Texture of Gossan is Rough, Sandy whereas that of Gneiss is Banded, Foliated, Platy. Gossan appears Dull and Banded and Gneiss appears Foliated. The luster of Gossan is metallic while that of Gneiss is dull. Gossan is available in brown, brown- black, gold, green, rust colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Gossan are cemetery markers, commemorative tablets, gemstone and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.