Definition
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
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 porfire, from Italian porfiro and in some cases directly from Latin porphyrites
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Group
Not Applicable
Plutonic
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Amorphous, Glassy
Porphyritic
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Black, Brown, Colourless, Green, Grey, Red, Rust, White
Durability
Durable
Durable
Appearance
Veined or Pebbled
Dull
Interior Uses
Not Yet Used
Decorative Aggregates, Interior Decoration
Exterior Uses
Not Yet Used
Garden Decoration, Paving Stone
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
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
Types
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Rhomb Porphyry
Features
Helps in production of Heat and Electricity, Used as fossil fuel
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not 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.
Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.
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
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Not Registered
Types of Erosion
Not Applicable
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Irregular
Porosity
Less Porous
Less Porous
Luster
Dull to Vitreous to Submetallic
Dull
Cleavage
Non-Existent
Imperfect
Toughness
Not Available
1.7
Specific Gravity
1.1-1.4
2.5-4
Transparency
Opaque
Translucent to Opaque
Density
1100-1400 g/cm3
2.5-2.52 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
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Egypt, Ethiopia, Ghana, South Africa
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, Cuba, Jamaica, USA
South America
Brazil, Chile, Colombia, Venezuela
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, Queensland, Victoria
New South Wales, New Zealand, Western Australia
Coal vs Porphyry 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 Porphyry characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Coal and Properties of Porphyry. Learn more about Coal vs Porphyry in the next section. The interior uses of Coal include Not yet used whereas the interior uses of Porphyry include Decorative aggregates and Interior decoration. Due to some exceptional properties of Coal and Porphyry, 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 Porphyry include Construction aggregate.
More about Coal and Porphyry
Here you can know more about Coal and Porphyry. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Coal and Porphyry 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 Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica. You can also check out the list of all Sedimentary Rocks. When we have to compare Coal vs Porphyry, 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, Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors. Appearance of Coal is Veined or Pebbled and that of Porphyry is Dull. Properties of rock is another aspect for Coal vs Porphyry. The hardness of Coal is 1-1.5 and that of Porphyry is 6-7. The types of Coal are Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite whereas types of Porphyry are Rhomb Porphyry. 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 Porphyry is white. The specific heat capacity of Coal is 1.32 kJ/Kg K and that of Porphyry 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 Porphyry is heat resistant, impact resistant.