Definition
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
Origin
USA
USA, Australia
Discoverer
John Peter Salley
Tornebohm
Etymology
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Amorphous, Glassy
Earthy, Mud-rich, Rough
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Veined or Pebbled
Dull
Interior Uses
-
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
-
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
-
Curbing
Construction Industry
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Endoskarns
Features
Helps in production of Heat and Electricity, Used as fossil fuel
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
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. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
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
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Irregular
Streak
Black
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Dull to Vitreous to Submetallic
Waxy and Dull
Specific Gravity
1.1-1.4
2.86
Transparency
Opaque
Opaque
Density
1100-1400 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
South Africa, 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
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada
South America
Brazil, Chile, Colombia, Venezuela
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, Queensland, Victoria
Central Australia, Western Australia
All about Coal and Skarn Properties
Know all about Coal and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Coal belongs to Sedimentary Rocks while Skarn belongs to Metamorphic Rocks.Texture of Coal is Amorphous, Glassy whereas that of Skarn is Earthy, Mud-rich, Rough. Coal appears Veined or Pebbled and Skarn appears Dull. The luster of Coal is dull to vitreous to submetallic while that of Skarn is waxy and dull. Coal is available in black, brown, dark brown, grey, light to dark grey colors whereas Skarn is available in black, brown, green, grey, white 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 Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).