Chert

Argillite

Chert and Argillite

Chert

Argillite

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Definition

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

Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate

History

Origin

Discoverer

Unknown

Etymology

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

From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite

Class

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Banded, Rough

Clastic, Polished

Color

Black, Brown, Green, Grey, Red, White

Dark Grey to Black, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Rough and Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

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

Fire resistant, Used to manufracture paperweights and bookends

Types

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

Metamorphic rock

Features

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

Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Formation

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.

An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.

Composition

Mineral Content

Quartz, Silicon

Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz

Compound Content

Silicon Dioxide

Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

6.5-72-3

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven, Splintery or Conchoidal

Conchoidal to Uneven

Streak

White

White to Grey

Porosity

Highly Porous

Luster

Waxy and Dull

Compressive Strength

450.00 N/mm²-

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.5

2.6

Specific Gravity

2.5-2.82.56-2.68

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³2.54-2.66 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Bangladesh, China, India, Russia

Africa

Kenya, Morocco, South Africa, Tanzania

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Europe

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

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

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

USA

South America

Bolivia, Brazil

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

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

All about Chert and Argillite Properties

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