Shale

Hornfels

Shale and Hornfels

Shale

Hornfels

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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

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

History

Origin

New Zealand

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 German which means hornstone

Class

Sedimentary Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic, Splintery

Granular, Platy

Color

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

Brown, Dark Greenish - Grey, Green, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

for Road Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Pottery

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

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

Biotite hornfels

Features

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

Smooth to touch

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. Hornfels 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

Andalusite

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

Fe, Mg

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

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

Properties

Physical Properties

Hardness

32-3

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Dull

Shiny

Compressive Strength

95.00 N/mm²5.80 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Perfect

Toughness

2.6

Specific Gravity

2.2-2.83.4-3.9

0 8.4

👆🏻

Transparency

Opaque

Density

2.4-2.8 g/cm³0.25-0.30 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.39 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

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

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Cameroon, East Africa, Tanzania, Western Africa

Europe

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

United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada, USA

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Bolivia, Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

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

New South Wales, New Zealand, Queensland, Western Australia

All about Shale and Hornfels Properties

Know all about Shale and Hornfels properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Hornfels belongs to Metamorphic Rocks.Texture of Shale is Clastic, Splintery whereas that of Hornfels is Granular, Platy. Shale appears Muddy and Hornfels appears Dull. The luster of Shale is dull while that of Hornfels is shiny. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. The commercial uses of Shale are creating artwork, pottery and that of Hornfels are cemetery markers, commemorative tablets, creating artwork.