Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Rhyolite is a fine-grained igneous rock which is rich in silica
Origin
France
North America
Discoverer
Alexandre Brongniart
Ferdinand von Richthofen
Etymology
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Clastic
Aphanitic, Glassy, Porphyritic
Color
Reddish Brown
Grey, White, Light Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Dull
Banded
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Whetstones
Not Yet Used
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts
Commercial Uses
In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Gemstone, Laboratory bench tops, Jewelry
Types
Not Available
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock
Acidic in nature, Available in lots of colors
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Used
Not Yet Used
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.
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
Mineral Content
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Regional 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, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Coarse Grained
Large and Coarse Grained
Fracture
Conchoidal
Sub-conchoidal
Porosity
Highly Porous
Highly Porous
Compressive Strength
Not Available
Cleavage
Not Available
Not Available
Toughness
Not Available
2
Specific Gravity
0
2.65-2.67
Transparency
Opaque
Opaque
Density
Not Available
2.4-2.6 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
China, India
Africa
Namibia, Nigeria, South Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Germany, Iceland, Ireland, Italy, Spain
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
New Zealand, Queensland, Western Australia