Definition
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals
History
Origin
Western Australia, Minnesota
-
Discoverer
Johann Gottlob Lehmann
R. J. Hauy
Etymology
From its formation process
From Greek pegma, pegmat which means- thing joined together + -ite
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Banded, Trellis
Pegmatitic
Color
Red, Reddish Brown
Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Layered, Banded, Veined and Shiny
Layered, Banded, Veined and Shiny
Architecture
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Paving Stone
Other Architectural Uses
Curbing, Whetstones
Curbing
Industry
Construction Industry
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts, Sculpture, Small Figurines
Other Uses
Commercial Uses
As a touchstone, Cemetery Markers, Creating Artwork
Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz
Types
Algoma-type , Lake Superior-type, Superior-type and Taconite
Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite
Features
Is one of the oldest rock
Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
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.
Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.
Composition
Mineral Content
Hematite, Magnetite, Quartz
Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz
Compound Content
Fe, Iron(III) Oxide, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Coastal Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
5.5-67
1
7
👆🏻
Grain Size
Large and Coarse Grained
Medium to Coarse Grained
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Streak
White
White
Porosity
Highly Porous
Less Porous
Luster
Earthy
Grainy, Pearly and Vitreous
Compressive Strength
220.00 N/mm2178.54 N/mm2
0.15
450
👆🏻
Cleavage
-
Perfect
Toughness
1.5
2.1
Specific Gravity
5.0-5.32.6-2.63
0
8.4
👆🏻
Transparency
Translucent to Opaque
Translucent to Opaque
Density
-9999 g/cm32.6-2.65 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
3.20 kJ/Kg K0.79 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea
Africa
Kenya, Morocco, South Africa, Tanzania
South Africa
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine
Others
Greenland, Mid-Atlantic Ridge
-
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada
South America
Bolivia, Brazil
Brazil
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
New South Wales, Queensland, South Australia, Western Australia