Definition
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Discoverer
Unknown
John Peter Salley
Etymology
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Porphyritic
Amorphous, Glassy
Color
Black, Brown, Green, Grey, Red, Rust, White
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull
Veined or Pebbled
Interior Uses
Decorative Aggregates, Interior Decoration
-
Exterior Uses
Garden Decoration, Paving Stone
-
Other Architectural Uses
Curbing
-
Construction Industry
Construction Aggregate
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Types
Rhomb Porphyry
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Features
Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny
Helps in production of Heat and Electricity, Used as fossil fuel
Archaeological Significance
Formation
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.
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.
Mineral Content
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
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
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering
-
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
-
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Irregular
Conchoidal
Porosity
Less Porous
Less Porous
Luster
Dull
Dull to Vitreous to Submetallic
Specific Gravity
2.5-4
1.1-1.4
Transparency
Translucent to Opaque
Opaque
Density
2.5-2.52 g/cm3
1100-1400 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
Egypt, Ethiopia, Ghana, South Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Deposits in Western Continents
North America
Canada, Cuba, Jamaica, USA
Canada, Mexico, USA
South America
Bolivia, Brazil, Colombia, Ecuador, Paraguay
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
New South Wales, Queensland, Victoria
All about Porphyry and Coal Properties
Know all about Porphyry and Coal properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry belongs to Igneous Rocks while Coal belongs to Sedimentary Rocks.Texture of Porphyry is Porphyritic whereas that of Coal is Amorphous, Glassy. Porphyry appears Dull and Coal appears Veined or Pebbled. The luster of Porphyry is dull while that of Coal is dull to vitreous to submetallic. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Coal is available in black, brown, dark brown, grey, light to dark grey colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Coal are alumina refineries, electricity generation, liquid fuel, manufacture of soap, solvents, dyes, plastics and fibres, paper industry.