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Coal
Coal

Hornfels
Hornfels



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Coal vs Hornfels

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Definition

Definition

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

USA
New Zealand

Discoverer

John Peter Salley
Unknown

Etymology

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

Class

Sedimentary Rocks
Metamorphic Rocks

Sub-Class

Durable Rock, Soft Rock
Durable Rock, Soft Rock

Family

Group

-
-

Other Categories

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

Texture

Texture

Amorphous, Glassy
Granular, Platy

Color

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

Maintenance

Less
Less

Durability

Durable
Durable

Water Resistant

Scratch Resistant

Stain Resistant

Wind Resistant

Acid Resistant

Appearance

Veined or Pebbled
Dull

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

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

Medical Industry

-
-

Antiquity Uses

Artifacts
Artifacts, Monuments

Other Uses

Commercial Uses

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

Types

Types

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

Features

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

Archaeological Significance

Monuments

-
-

Famous Monuments

-
-

Sculpture

-
-

Famous Sculptures

-
-

Pictographs

-
-

Petroglyphs

-
-

Figurines

-
-

Fossils

Present
Absent

Formation

Formation

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.
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

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
Andalusite

Compound Content

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

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

1-1.52-3
1 7
👆🏻

Grain Size

Medium to Fine Coarse Grained
Fine Grained

Fracture

Conchoidal
Conchoidal

Streak

Black
-

Porosity

Less Porous
Highly Porous

Luster

Dull to Vitreous to Submetallic
Shiny

Compressive Strength

-5.80 N/mm2
0.15 450
👆🏻

Cleavage

-
Perfect

Toughness

-
-

Specific Gravity

1.1-1.43.4-3.9
0 8.4
👆🏻

Transparency

Opaque
Opaque

Density

1100-1400 g/cm30.25-0.30 g/cm3
0 1400
👆🏻

Thermal Properties

Specific Heat Capacity

1.32 kJ/Kg K0.84 kJ/Kg K
0.14 3.2
👆🏻

Resistance

Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Africa

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

Europe

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

Others

-
-

Deposits in Western Continents

North America

Canada, Mexico, USA
Canada, USA

South America

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

Deposits in Oceania Continent

Australia

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

Coal vs Hornfels 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 Coal and Hornfels Reserves. Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds. 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. 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 Coal vs Hornfels information and Coal vs Hornfels characteristics in the upcoming sections.

Coal vs Hornfels 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. Coal vs Hornfels characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Coal and Properties of Hornfels. Learn more about Coal vs Hornfels in the next section. The interior uses of Coal include whereas the interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Coal and Hornfels, they have various applications in construction industry. The uses of Coal in construction industry include Cement manufacture, For road aggregate, Making natural cement, Steel production and that of Hornfels include For road aggregate, Roadstone.

More about Coal and Hornfels

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