Shale

Pseudotachylite

Shale and Pseudotachylite

Shale

Pseudotachylite

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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

Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.

History

Origin

USA

Discoverer

Johann Gottlob Lehmann

Unknown

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 pseudo- +‎ tachylite, a glassy rock generated by frictional heat within faults.

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

Quench

Color

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

Black, Brown, Green, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Dull and Soft

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

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 Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Pottery

Creating Artwork, Gemstone

Types

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

Cataclastic rock

Features

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

Host Rock for Lead

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. Pseudotachylite 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

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact 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

1 7

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Grain Size

Very fine-grained

Fracture

Uneven

Streak

White

Light to dark brown

Porosity

Highly Porous

Less Porous

Luster

Dull

Vitreous

Compressive Strength

95.00 N/mm²60.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.6

Specific Gravity

2.2-2.82.46-2.86

0 8.4

👆🏻

Transparency

Opaque

Transparent to Translucent

Density

2.4-2.8 g/cm³2.7-2.9 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

South Korea

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Western Africa

Europe

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

Great Britain, Switzerland

Others

Deposits in Western Continents

North America

USA

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

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

Central Australia, Western Australia

All about Shale and Pseudotachylite Properties

Know all about Shale and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Shale is Clastic, Splintery whereas that of Pseudotachylite is Quench. Shale appears Muddy and Pseudotachylite appears Dull and Soft. The luster of Shale is dull while that of Pseudotachylite is vitreous. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Shale are creating artwork, pottery and that of Pseudotachylite are creating artwork, gemstone.