Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age
Origin
Italy
Western Australia, Minnesota
Discoverer
Unknown
Johann Gottlob Lehmann
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From its formation process
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Porphyritic
Banded, Trellis
Color
Blue, Bluish - Grey
Red, Reddish Brown
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Layered, Banded, Veined and Shiny
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Curbing, Whetstones
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
As Dimension Stone, Used for flooring, stair treads, borders and window sills.
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers
As a touchstone, Cemetery Markers, Creating Artwork
Types
Rhyolite
Algoma-type , Lake Superior-type, Superior-type and Taconite
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Is one of the oldest rock
Archaeological Significance
Formation
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.
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.
Mineral Content
Albite, Amphibole, Quartz
Hematite, Magnetite, Quartz
Compound Content
Al, Fe, Potassium Oxide
Fe, Iron(III) Oxide, Silicon Dioxide
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering
Types of Erosion
Coastal Erosion, Water Erosion
Coastal Erosion, Wind Erosion
Grain Size
Medium Grained
Large and Coarse Grained
Fracture
Pervasive
Uneven, Splintery or Conchoidal
Streak
Bluish Black
White
Porosity
Highly Porous
Highly Porous
Specific Gravity
2.38
5.0-5.3
Transparency
Opaque
Translucent to Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China
China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
East Africa
Kenya, Morocco, South Africa, Tanzania
Europe
Italy
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
-
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
-
Canada, Mexico, USA
South America
-
Bolivia, Brazil
Deposits in Oceania Continent
Australia
Queensland
New South Wales, Queensland, South Australia, Western Australia