Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Origin
France
Romania and Moldova, Europe
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 Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic
Aphanitic to Porphyritic
Color
Reddish Brown
Bluish - Grey, Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Rough and Dull
Vesicular
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Whetstones
Curbing
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts
Commercial Uses
In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Commemorative Tablets, Creating Artwork
Types
Arkose
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock
Host Rock for Lead, Is one of the oldest 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.
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Mineral Content
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion
Grain Size
Coarse Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Less Porous
Luster
Dull
Subvitreous to Dull
Specific Gravity
0
2.86-2.87
Transparency
Opaque
Translucent
Density
-9999 g/cm3
2.77-2.771 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
-
Africa
Namibia, Nigeria, South Africa
-
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
France, Greece, Romania, Scotland, Spain
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
New Zealand, South Australia, Western Australia