Definition
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Marl is an unconsolidated sedimentary rock consisting of clay and lime
Discoverer
John Peter Salley
Unknown
Etymology
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
From Old French marle, from Late Latin marglia
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Amorphous, Glassy
Earthy
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Beige, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Veined or Pebbled
Rough and Dull
Interior Uses
Not Yet Used
Decorative Aggregates, Floor Tiles
Exterior Uses
Not Yet Used
As Building Stone, Roof Tiles
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Jewellery, Sculpture, Small Figurines
Commercial Uses
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Creating Artwork, Soil Conditioner
Types
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Clay Marl ,Blue Marl, Red Marl, High Bank Marl, Shell Layer Marl, Under Shell Layer Marl, Sand Marl, Green Marl, Grey Marl and Clayey Marl
Features
Helps in production of Heat and Electricity, Used as fossil fuel
Generally rough to touch, Is one of the oldest rock, Splintery, Very fine grained rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Used
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.
Marl forms when very fine-grained clay particles are deposited in water which settles at the bottom of water bodies and are compacted by overlying sediment; the water squeezes out and hence forming Marl rock.
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, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering
Types of Erosion
Not Applicable
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
Dull
Cleavage
Non-Existent
Not Available
Toughness
Not Available
2.6
Specific Gravity
1.1-1.4
2.2-2.8
Transparency
Opaque
Opaque
Density
1100-1400 g/cm3
2.4-2.8 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
India, Pakistan, Russia
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Ethiopia, Kenya, Morocco, South Africa
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Brazil, Chile, Colombia, Venezuela
Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, Queensland, Victoria
New South Wales, Victoria, Western Australia
Coal vs Marl 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 Marl characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Coal and Properties of Marl. Learn more about Coal vs Marl in the next section. The interior uses of Coal include Not yet used whereas the interior uses of Marl include Decorative aggregates and Floor tiles. Due to some exceptional properties of Coal and Marl, 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 Marl include Cement manufacture, Construction aggregate, For road aggregate, Making natural cement, Raw material for the manufacture of mortar.
More about Coal and Marl
Here you can know more about Coal and Marl. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Coal and Marl 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 Marl includes Calcite, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz. You can also check out the list of all Sedimentary Rocks. When we have to compare Coal vs Marl, 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, Marl is available in beige, brown, green, grey, white colors. Appearance of Coal is Veined or Pebbled and that of Marl is Rough and Dull. Properties of rock is another aspect for Coal vs Marl. The hardness of Coal is 1-1.5 and that of Marl is 2-3. The types of Coal are Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite whereas types of Marl are Clay Marl ,Blue Marl, Red Marl, High Bank Marl, Shell Layer Marl, Under Shell Layer Marl, Sand Marl, Green Marl, Grey Marl and Clayey Marl. 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 Marl is white. The specific heat capacity of Coal is 1.32 kJ/Kg K and that of Marl is Not Available. 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 Marl is heat resistant, impact resistant.