Definition
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorthosite, or a pyroxene-depleted relative of gabbro
Discoverer
Alexandre Brongniart
Christian Leopold von Buch
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 Troklotit, from Greek trōktēs, a marine fish (taken to be trout)
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Clastic
Phaneritic
Color
Reddish Brown
Dark Grey to Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Dull
Veined and Shiny
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Bathrooms, Countertops, Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration, Kitchens
Exterior Uses
Paving Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
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, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Jewellery, Monuments, Sculpture
Commercial Uses
In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Arkose
Ultramafic rock
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock
Smooth to touch
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.
Troctolite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Augite, Olivine, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Mechanical Weathering
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Coarse Grained
Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Highly Porous
Specific Gravity
0
2.86-2.87
Transparency
Opaque
Opaque
Density
-9999 g/cm3
2.7-3.3 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
India, Russia
Africa
Namibia, Nigeria, South Africa
South Africa
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Germany, Greece, Italy, Scotland, Turkey
Others
Greenland
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
New Zealand, Queensland