Shale

Chert

Shale and Chert

Shale

Chert

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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

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

History

Origin

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 flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

Class

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic, Splintery

Banded, Rough

Color

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

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Pottery

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

Types

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

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

Features

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

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Archaeological Significance

Monuments

Famous Monuments

Jantar Mantar in India

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

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.

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

Composition

Mineral Content

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

Quartz, Silicon

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

36.5-7

1 7

👆🏻

Grain Size

Very fine-grained

Fracture

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Dull

Waxy and Dull

Compressive Strength

95.00 N/mm²450.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.6

1.5

Specific Gravity

2.2-2.82.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.4-2.8 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.39 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Kenya, Morocco, South Africa, Tanzania

Europe

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

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Bolivia, Brazil

Deposits in Oceania Continent

Australia

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

New South Wales, Queensland, South Australia, Western Australia

All about Shale and Chert Properties

Know all about Shale and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Shale and Chert belong to Sedimentary Rocks.Texture of Shale is Clastic, Splintery whereas that of Chert is Banded, Rough. Shale appears Muddy and Chert appears Glassy or Pearly. The luster of Shale is dull while that of Chert is waxy and dull. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Shale are creating artwork, pottery and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.