Marl

Chert

Marl and Chert

Marl

Chert

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Definition

Marl is an unconsolidated sedimentary rock consisting of clay and lime

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

History

Origin

Discoverer

William Smith

Unknown

Etymology

From Old French marle, from Late Latin marglia

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, Soft Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Earthy

Banded, Rough

Color

Beige, Brown, Green, Grey, White

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Rough and Dull

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles

Decorative Aggregates, Homes

Exterior Uses

As Building Stone, Roof Tiles

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, Jewellery, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Soil Conditioner

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

Types

Clay Marl ,Blue Marl, Red Marl, High Bank Marl, Shell Layer Marl, Under Shell Layer Marl, Sand Marl, Green Marl, Grey Marl and Clayey Marl

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

Features

Generally rough to touch, Is one of the oldest rock, Splintery, 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

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Formation

Marl forms when very fine-grained clay particles are deposited in water which settles at the bottom of water bodies and are compacted by overlying sediment; the water squeezes out and hence forming Marl rock.

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

Calcite, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz

Quartz, Silicon

Compound Content

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, Silicon Dioxide

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

2-36.5-7

1 7

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Grain Size

Very fine-grained

Fracture

Conchoidal

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Dull

Waxy and Dull

Compressive Strength

30.00 N/mm²450.00 N/mm²

0.15 450

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Cleavage

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

0.80 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

India, Pakistan, Russia

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

Africa

Ethiopia, Kenya, Morocco, South Africa

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

Colombia, Ecuador, Peru

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, Victoria, Western Australia

New South Wales, Queensland, South Australia, Western Australia

All about Marl and Chert Properties

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