Arkose and Coquina
Definition
Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically-sorted fragments of the shells of molluscs, trilobites, brachiopods, or other invertebrates
History
Origin
France
European Foreland Basins
Discoverer
Alexandre Brongniart
Unknown
Etymology
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Texture
Clastic
Clastic
Color
Reddish Brown
Beige, Buff, Orange
Maintenance
Less
More
Durability
Durable
Non-Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
Yes
No
Wind Resistant
No
No
Acid Resistant
Yes
No
Appearance
Rough and Dull
Layered, Banded, Veined and Shiny
Uses
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
Garden Decoration, Office Buildings
Other Architectural Uses
Whetstones
Curbing
Industry
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
Building houses or walls, Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Creating Artwork
Types
Types
Not Available
Not Available
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock
Available in Lots of Colors and Patterns, Is one of the oldest rock
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Used
Fossils
Present
Present
Formation
Formation
Arkose rock forms from the weathering of feldspar-rich igneous or metamorphic rock, most commonly granitic rocks, which are primarily composed of quartz and feldspar.
Coquina is a sedimentary rock which is formed when billions of small clam-like seashell, called Coquina, or cockleshell are die and hence are deposited, buried and turns into a rock when pressure is applied.
Composition
Mineral Content
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Transformation
Metamorphism
No
No
Types of Metamorphism
Not Applicable
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
6-7
1-2
Grain Size
Coarse Grained
Coarse Grained
Fracture
Conchoidal
Irregular
Streak
White
White
Porosity
Highly Porous
Highly Porous
Luster
Dull
Dull to Vitreous to Submetallic
Cleavage
Not Available
Not Available
Toughness
Not Available
Not Available
Specific Gravity
0
1.10-2.24
Transparency
Opaque
Opaque
Density
Not Available
2.8-2.9 g/cm3
Thermal Properties
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Not Yet Found
Africa
Namibia, Nigeria, South Africa
Not Yet Found
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
United Kingdom
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
Not Yet Found
All about Arkose and Coquina Properties
Know all about Arkose and Coquina properties here. All properties of rocks are important as they define the type of rock and its application. Arkose and Coquina belong to Sedimentary Rocks.Texture of Arkose is Clastic whereas that of Coquina is Clastic. Arkose appears Rough and Dull and Coquina appears Layered, Banded, Veined and Shiny. The luster of Arkose is dull while that of Coquina is dull to vitreous to submetallic. Arkose is available in reddish brown colors whereas Coquina is available in beige, buff, orange colors. The commercial uses of Arkose are in aquifers, soil conditioner, source of magnesia (mgo), tombstones and that of Coquina are creating artwork.
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