Definition
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
  
Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix
  
History
  
  
Origin
Western Australia, Minnesota
  
Egypt
  
Discoverer
Unknown
  
Unknown
  
Etymology
From its formation process
  
From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites
  
Class
Sedimentary Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Plutonic
  
Other Categories
Coarse Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Banded, Trellis
  
Porphyritic
  
Color
Red, Reddish Brown
  
Black, Brown, Colourless, Green, Grey, Red, Rust, White
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
No
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
Yes
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
Yes
  
Appearance
Layered, Banded, Veined and Shiny
  
Dull
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes
  
Decorative Aggregates, Interior Decoration
  
Exterior Uses
Paving Stone, Office Buildings
  
Garden Decoration, Paving Stone
  
Other Architectural Uses
Curbing, Whetstones
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
  
Construction Aggregate
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts, Monuments, Sculpture
  
Other Uses
  
  
Commercial Uses
As a touchstone, Cemetery Markers, Creating Artwork
  
Creating Artwork, Gemstone, Jewelry
  
Types
Algoma-type , Lake Superior-type, Superior-type and Taconite
  
Rhomb Porphyry
  
Features
Is one of the oldest rock
  
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
  
Fossils
Present
  
Absent
  
Formation
The banded iron layers are formed in sea water when oxygen is released by photosynthetic cyano-bacteria. The oxygen then combines with dissolved iron in ocean to form insoluble iron oxides, which precipitated out, forming a thin layer of banded iron formation on ocean floor.
  
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.
  
Composition
  
  
Mineral Content
Hematite, Magnetite, Quartz
  
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
  
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
  
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Chemical Weathering
  
Biological Weathering, Chemical Weathering, Not Registered
  
Erosion
Yes
  
Yes
  
Types of Erosion
Coastal Erosion, Wind Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion
  
Physical Properties
  
  
Hardness
5.5-6
  
6-7
  
Grain Size
Large and Coarse Grained
  
Fine Grained
  
Fracture
Uneven, Splintery or Conchoidal
  
Irregular
  
Streak
White
  
White
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Earthy
  
Dull
  
Cleavage
Imperfect
  
Imperfect
  
Toughness
1.5
  
1.7
  
Specific Gravity
5.0-5.3
  
2.5-4
  
Transparency
Translucent to Opaque
  
Translucent to Opaque
  
Density
Not Available
  
2.5-2.52 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
3.20 kJ/Kg K
  
1
Not Available
  
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant
  
Deposits in Eastern Continents
  
  
Asia
China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
  
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
  
Africa
Kenya, Morocco, South Africa, Tanzania
  
Egypt, Ethiopia, Ghana, South Africa
  
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
  
Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland
  
Others
Greenland, Mid-Atlantic Ridge
  
Greenland
  
Deposits in Western Continents
  
  
North America
Canada, Mexico, USA
  
Canada, Cuba, Jamaica, USA
  
South America
Bolivia, Brazil
  
Bolivia, Brazil, Colombia, Ecuador, Paraguay
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, Queensland, South Australia, Western Australia
  
New South Wales, New Zealand, Western Australia
  
Banded iron formation 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. Banded iron formation vs Porphyry characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Banded iron formation and Properties of Porphyry. Learn more about Banded iron formation vs Porphyry in the next section. The interior uses of Banded iron formation include Decorative aggregates and Homes whereas the interior uses of Porphyry include Decorative aggregates and Interior decoration. Due to some exceptional properties of Banded iron formation and Porphyry, they have various applications in construction industry. The uses of Banded iron formation in construction industry include As dimension stone, Used for flooring, stair treads, borders and window sills. and that of Porphyry include Construction aggregate.
More about Banded iron formation and Porphyry
Here you can know more about Banded iron formation and Porphyry. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Banded iron formation and Porphyry consists of mineral content and compound content. The mineral content of Banded iron formation includes Hematite, Magnetite, Quartz 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 Banded iron formation vs Porphyry, the texture, color and appearance plays an important role in determining the type of rock. Banded iron formation is available in red, reddish brown colors whereas, Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors. Appearance of Banded iron formation is Layered, Banded, Veined and Shiny and that of Porphyry is Dull. Properties of rock is another aspect for Banded iron formation vs Porphyry. The hardness of Banded iron formation is 5.5-6 and that of Porphyry is 6-7. The types of Banded iron formation are Algoma-type , Lake Superior-type, Superior-type and Taconite 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 Banded iron formation and Porphyry is white. The specific heat capacity of Banded iron formation is 3.20 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.Banded iron formation is heat resistant, impact resistant, pressure resistant, wear resistant whereas Porphyry is heat resistant, impact resistant.