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Hornfels
Hornfels

Coal
Coal



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Hornfels
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Coal

Hornfels vs Coal

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Definition

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
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds

History

Origin

New Zealand
USA

Discoverer

Unknown
John Peter Salley

Etymology

From German which means hornstone
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century

Class

Metamorphic Rocks
Sedimentary Rocks

Sub-Class

Durable Rock, Soft Rock
Durable Rock, Soft Rock

Family

Group

-
-

Other Categories

Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Texture

Granular, Platy
Amorphous, Glassy

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Dark Brown, Grey, Light to Dark Grey

Maintenance

Less
Less

Durability

Durable
Durable

Water Resistant

Scratch Resistant

Stain Resistant

Wind Resistant

Acid Resistant

Appearance

Dull
Veined or Pebbled

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration
-

Exterior Uses

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

Other Architectural Uses

Curbing
-

Industry

Construction Industry

for Road Aggregate, Roadstone
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production

Medical Industry

-
-

Antiquity Uses

Artifacts, Monuments
Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry

Types

Types

Biotite hornfels
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite

Features

Smooth to touch
Helps in production of Heat and Electricity, Used as fossil fuel

Archaeological Significance

Monuments

-
-

Famous Monuments

-
-

Sculpture

-
-

Famous Sculptures

-
-

Pictographs

-
-

Petroglyphs

-
-

Figurines

-
-

Fossils

Absent
Present

Formation

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.
Coal forms from the accumulation of plant debris in a swamp environment which is buried by sediments such as mud or sand and then compacted to form coal.

Composition

Mineral Content

Andalusite
Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon

Compound Content

Fe, Mg
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur

Transformation

Metamorphism

Types of Metamorphism

-
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

Types of Weathering

Biological Weathering
-

Erosion

Types of Erosion

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

Properties

Physical Properties

Hardness

2-31-1.5
1 7
👆🏻

Grain Size

Fine Grained
Medium to Fine Coarse Grained

Fracture

Conchoidal
Conchoidal

Streak

-
Black

Porosity

Highly Porous
Less Porous

Luster

Shiny
Dull to Vitreous to Submetallic

Compressive Strength

5.80 N/mm2-
0.15 450
👆🏻

Cleavage

Perfect
-

Toughness

-
-

Specific Gravity

3.4-3.91.1-1.4
0 8.4
👆🏻

Transparency

Opaque
Opaque

Density

0.25-0.30 g/cm31100-1400 g/cm3
0 1400
👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K1.32 kJ/Kg K
0.14 3.2
👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam

Africa

Cameroon, East Africa, Tanzania, Western Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania

Europe

United Kingdom
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom

Others

-
-

Deposits in Western Continents

North America

Canada, USA
Canada, Mexico, USA

South America

Bolivia, Brazil, Colombia, Ecuador
Brazil, Chile, Colombia, Venezuela

Deposits in Oceania Continent

Australia

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

Hornfels vs Coal Information

Earth’s outer layer is covered by rocks and these rocks have different physical and chemical properties. As two rocks are not same, it’s fun to compare them. You can also know more about Hornfels and Coal Reserves. 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. Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds. These rocks are composed of many distinct minerals. The process of formation of rocks is different for various rocks. Rocks are quarried from many years for various purposes. You can check out Hornfels vs Coal information and Hornfels vs Coal characteristics in the upcoming sections.

Hornfels vs Coal Characteristics

Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Hornfels vs Coal characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Coal. Learn more about Hornfels vs Coal in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Coal include . Due to some exceptional properties of Hornfels and Coal, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Coal include Cement manufacture, For road aggregate, Making natural cement, Steel production.

More about Hornfels and Coal

Here you can know more about Hornfels and Coal. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Coal consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Coal includes Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Coal, the texture, color and appearance plays an important role in determining the type of rock. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas, Coal is available in black, brown, dark brown, grey, light to dark grey colors. Appearance of Hornfels is Dull and that of Coal is Veined or Pebbled. Properties of rock is another aspect for Hornfels vs Coal. The hardness of Hornfels is 2-3 and that of Coal is 1-1.5. The types of Hornfels are Biotite hornfels whereas types of Coal are Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Hornfels is while that of Coal is black. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Coal is 1.32 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Hornfels is heat resistant, impact resistant, pressure resistant whereas Coal is heat resistant.