Coal

Hornfels

Coal and Hornfels

Coal

Hornfels

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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

Family

Group

Other Categories

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

Fine Grained Rock, Opaque Rock

Texture

Amorphous, Glassy

Granular, Platy

Color

Black, Brown, Dark Brown, Grey, Light to Dark Grey

Brown, Dark Greenish - Grey, Green, Reddish Brown

Maintenance

Less

Durability

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

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

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

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

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

All about Coal and Hornfels Properties

Know all about Coal and Hornfels properties here. All properties of rocks are important as they define the type of rock and its application. Coal belongs to Sedimentary Rocks while Hornfels belongs to Metamorphic Rocks.Texture of Coal is Amorphous, Glassy whereas that of Hornfels is Granular, Platy. Coal appears Veined or Pebbled and Hornfels appears Dull. The luster of Coal is dull to vitreous to submetallic while that of Hornfels is shiny. 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. The commercial uses of Coal are alumina refineries, electricity generation, liquid fuel, manufacture of soap, solvents, dyes, plastics and fibres, paper industry and that of Hornfels are cemetery markers, commemorative tablets, creating artwork.