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
It is a metamorphic magnesium rich rock because it is composed of the mineral talc
History
Origin
-
USA
Discoverer
Unknown
Unknown
Etymology
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
From 17th century, because of its greasy feel and use like a soap
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Polished
Polished
Color
Dark Grey to Black, Pink, Red, White
Black, Black to Grey, Green, Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Rough and Dull
Dull, Banded and Foilated
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Bathrooms, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings
As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Curbing
Industry
Construction Industry
Used for flooring, stair treads, borders and window sills.
Manufacture of Magnesium and Dolomite Refractories
Medical Industry
-
Taken as a Supplement for Calcium or Magnesium
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Jewellery, Monuments, Sculpture
Other Uses
Commercial Uses
Fire resistant, Used to manufracture paperweights and bookends
Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)
Types
Metamorphic rock
Metamorphic rock
Features
Is one of the oldest rock
Host Rock for Lead
Archaeological Significance
Monuments
-
-
Famous Monuments
-
Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Present
Absent
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.
Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.
Composition
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz
Compound Content
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
CaO, Mg, MgO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion
-
Physical Properties
Hardness
2-31
1
7
👆🏻
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal to Uneven
Conchoidal
Streak
White to Grey
Black
Porosity
Highly Porous
Less Porous
Luster
Waxy and Dull
Greasy
Compressive Strength
-225.00 N/mm2
0.15
450
👆🏻
Cleavage
Slaty
Perfect
Toughness
2.6
1
Specific Gravity
2.56-2.682.86
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.54-2.66 g/cm32.8-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.87 kJ/Kg K0.88 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Egypt, Ethiopia, Ghana, South Africa, Western Africa
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom
Others
-
-
Deposits in Western Continents
North America
USA
Canada, USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Colombia
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
Central Australia, New Zealand, Queensland