Hornfels

Marl

Hornfels and Marl

Hornfels

Marl

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Definition

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock

Marl is an unconsolidated sedimentary rock consisting of clay and lime

History

Origin

New Zealand

Discoverer

Unknown

William Smith

Etymology

From German which means hornstone

From Old French marle, from Late Latin marglia

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Granular, Platy

Earthy

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Beige, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Rough and Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Floor Tiles

Exterior Uses

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

As Building Stone, Roof Tiles

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

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

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Jewellery, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Creating Artwork, Soil Conditioner

Types

Biotite hornfels

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

Features

Smooth to touch

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

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.

Composition

Mineral Content

Andalusite

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

Compound Content

Fe, Mg

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-32-3

1 7

👆🏻

Grain Size

Fine Grained

Very fine-grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Shiny

Dull

Compressive Strength

5.80 N/mm²30.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.6

Specific Gravity

3.4-3.92.2-2.8

0 8.4

👆🏻

Transparency

Opaque

Density

0.25-0.30 g/cm³2.4-2.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.80 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand

India, Pakistan, Russia

Africa

Cameroon, East Africa, Tanzania, Western Africa

Ethiopia, Kenya, Morocco, South Africa

Europe

United Kingdom

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

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Bolivia, Brazil, Colombia, Ecuador

Colombia, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

New South Wales, Victoria, Western Australia

All about Hornfels and Marl Properties

Know all about Hornfels and Marl properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Marl belongs to Sedimentary Rocks.Texture of Hornfels is Granular, Platy whereas that of Marl is Earthy. Hornfels appears Dull and Marl appears Rough and Dull. The luster of Hornfels is shiny while that of Marl is dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Marl is available in beige, brown, green, grey, white colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Marl are creating artwork, soil conditioner.