Shale

Skarn

Shale and Skarn

Shale

Skarn

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Definition

Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles

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

USA, Australia

Discoverer

Johann Gottlob Lehmann

Tornebohm

Etymology

From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,

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

Class

Sedimentary Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic, Splintery

Earthy, Mud-rich, Rough

Color

Black, Brown, Buff, Green, Grey, Red, Yellow

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

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, Sculpture

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Pottery

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

Types

Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale

Endoskarns

Features

Easily splits into thin plates, Generally rough to touch, Very fine grained rock

Host Rock for Lead, Zinc and Copper Deposits

Archaeological Significance

Monuments

Famous Monuments

Jantar Mantar in India

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.

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

Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides

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

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

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

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

36.5

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Irregular

Streak

White

Light to dark brown

Porosity

Highly Porous

Less Porous

Luster

Dull

Waxy and Dull

Compressive Strength

95.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.6

2.4

Specific Gravity

2.2-2.82.86

0 8.4

👆🏻

Transparency

Opaque

Density

2.4-2.8 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.39 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

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

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

South Africa, Western Africa

Europe

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Brazil, Colombia, Paraguay

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

Central Australia, Western Australia

All about Shale and Skarn Properties

Know all about Shale and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Skarn belongs to Metamorphic Rocks.Texture of Shale is Clastic, Splintery whereas that of Skarn is Earthy, Mud-rich, Rough. Shale appears Muddy and Skarn appears Dull. The luster of Shale is dull while that of Skarn is waxy and dull. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Skarn is available in black, brown, green, grey, white colors. The commercial uses of Shale are creating artwork, pottery and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).