Hornfels

Coal

Hornfels and Coal

Hornfels

Coal

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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

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

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

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

Texture

Granular, Platy

Amorphous, Glassy

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

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

Maintenance

Less

Durability

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

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

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

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

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

All about Hornfels and Coal Properties

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