Definition
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Origin
Western Australia, Minnesota
Italy
Discoverer
Unknown
Unknown
Etymology
From its formation process
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Banded, Trellis
Porphyritic
Color
Red, Reddish Brown
Blue, Bluish - Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Layered, Banded, Veined and Shiny
Foliated
Interior Uses
Decorative Aggregates, Homes
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Curbing
Construction Industry
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
As a touchstone, Cemetery Markers, Creating Artwork
Cemetery Markers
Types
Algoma-type , Lake Superior-type, Superior-type and Taconite
Rhyolite
Features
Is one of the oldest rock
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Not Yet Used
Not Yet Used
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.
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Hematite, Magnetite, Quartz
Albite, Amphibole, Quartz
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
Al, Fe, Potassium Oxide
Types of Metamorphism
Not Applicable
Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Wind Erosion
Coastal Erosion, Water Erosion
Grain Size
Large and Coarse Grained
Medium Grained
Fracture
Uneven, Splintery or Conchoidal
Pervasive
Streak
White
Bluish Black
Porosity
Highly Porous
Highly Porous
Compressive Strength
Not Available
Cleavage
Imperfect
Not Available
Specific Gravity
5.0-5.3
2.38
Transparency
Translucent to Opaque
Opaque
Density
Not Available
Not Available
Specific Heat Capacity
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
Africa
Kenya, Morocco, South Africa, Tanzania
East Africa
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Italy
Others
Greenland, Mid-Atlantic Ridge
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Not Yet Found
South America
Bolivia, Brazil
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
Queensland