Skarn

Gneiss

Skarn and Gneiss

Skarn

Gneiss

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Definition

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

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

USA, Australia

Discoverer

Tornebohm

Unknown

Etymology

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

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

Class

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Earthy, Mud-rich, Rough

Banded, Foliated, Platy

Color

Black, Brown, Green, Grey, White

Black, Brown, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Countertops, Decorative Aggregates, Flooring, Interior Decoration

Exterior Uses

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As Dimension Stone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

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

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

Types

Endoskarns

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

Features

Host Rock for Lead, Zinc and Copper Deposits

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

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.

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

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

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

Compound Content

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

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

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

Impact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Properties

Physical Properties

Hardness

6.57

1 7

👆🏻

Grain Size

Fine Grained

Medium to Coarse Grained

Fracture

Irregular

Streak

Light to dark brown

White

Porosity

Less Porous

Very Less Porous

Luster

Waxy and Dull

Dull

Compressive Strength

70.00 N/mm²125.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.4

1.2

Specific Gravity

2.862.5-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.8-2.9 g/cm³2.6-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.70 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

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

Africa

South Africa, Western Africa

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

Europe

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

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

South America

Brazil, Colombia, Paraguay

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

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Skarn and Gneiss Properties

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