Definition
Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
Unknown
Unknown
Etymology
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Polished
Quench
Color
Dark Grey to Black, Pink, Red, White
Black, Brown, Colourless, Green, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Dull
Dull and Soft
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Curbing
Construction Industry
Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Commercial Uses
Fire resistant, Used to manufracture paperweights and bookends
Creating Artwork, Gemstone
Types
Not Available
Not Available
Features
Is one of the oldest rock
Host Rock for Lead
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Used
Not Yet Used
Formation
An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering
Not Applicable
Types of Erosion
Chemical Erosion
Not Applicable
Grain Size
Fine Grained
Very fine-grained
Fracture
Conchoidal to Uneven
Uneven
Streak
White to Grey
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Waxy and Dull
Vitreous
Compressive Strength
Not Available
Toughness
2.6
Not Available
Specific Gravity
2.56-2.68
2.46-2.86
Transparency
Opaque
Transparent to Translucent
Density
2.54-2.66 g/cm3
2.7-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
South Korea
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Western Africa
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Great Britain, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Not Yet Found
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
Central Australia, Western Australia
All about Argillite and Pseudotachylite Properties
Know all about Argillite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Argillite belongs to Sedimentary Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Argillite is Clastic, Polished whereas that of Pseudotachylite is Quench. Argillite appears Rough and Dull and Pseudotachylite appears Dull and Soft. The luster of Argillite is waxy and dull while that of Pseudotachylite is vitreous. Argillite is available in dark grey to black, pink, red, white colors whereas Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. The commercial uses of Argillite are fire resistant, used to manufracture paperweights and bookends and that of Pseudotachylite are creating artwork, gemstone.