Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Origin
France
Adak, Aleutian Islands
Discoverer
Alexandre Brongniart
Defant and Drummond
Etymology
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
From Adak, Aleutian Islands
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic
Porphyritic
Color
Reddish Brown
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Appearance
Rough and Dull
Dull and Soft
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Whetstones
Whetstones
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Monuments, Sculpture, Small Figurines
Commercial Uses
In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Commemorative Tablets, Pottery, Used in aquariums
Types
Arkose
Intermediate volcanic rock
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Archaeological Significance
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.
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
Mineral Content
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Olivine, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Aluminium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
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Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Grain Size
Coarse Grained
Fine to Medium Grained
Fracture
Conchoidal
Conchoidal
Streak
White
Bluish Black
Porosity
Highly Porous
Less Porous
Luster
Dull
Grainy, Pearly and Vitreous
Transparency
Opaque
Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
India, Russia
Africa
Namibia, Nigeria, South Africa
Ethiopia, Somalia, South Africa
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Iceland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
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