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
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Discoverer
Unknown
Unknown
Etymology
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Polished
Banded, Rough
Color
Dark Grey to Black, Pink, Red, White
Black, Brown, Green, Grey, Red, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Dull
Glassy or Pearly
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing, Whetstones
Curbing
Construction Industry
Used for flooring, stair treads, borders and window sills.
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Commercial Uses
Fire resistant, Used to manufracture paperweights and bookends
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Types
Metamorphic rock
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Features
Is one of the oldest rock
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Archaeological Significance
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.
Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Quartz, Silicon
Compound Content
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
Silicon Dioxide
Types of Metamorphism
-
-
Types of Weathering
Biological Weathering
-
Types of Erosion
Chemical Erosion
Chemical Erosion
Grain Size
Fine Grained
Very fine-grained
Fracture
Conchoidal to Uneven
Uneven, Splintery or Conchoidal
Streak
White to Grey
White
Porosity
Highly Porous
Highly Porous
Luster
Waxy and Dull
Waxy and Dull
Specific Gravity
2.56-2.68
2.5-2.8
Transparency
Opaque
Translucent to Opaque
Density
2.54-2.66 g/cm3
2.7 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Kenya, Morocco, South Africa, Tanzania
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
-
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
USA
Canada, Mexico, USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Bolivia, Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New South Wales, Queensland, South Australia, Western Australia
Argillite vs Chert Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Argillite vs Chert characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Argillite and Properties of Chert. Learn more about Argillite vs Chert in the next section. The interior uses of Argillite include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Chert include Decorative aggregates and Homes. Due to some exceptional properties of Argillite and Chert, they have various applications in construction industry. The uses of Argillite in construction industry include Used for flooring, stair treads, borders and window sills. and that of Chert include Arrowheads, Construction aggregate, Cutting tool, Spear points.
More about Argillite and Chert
Here you can know more about Argillite and Chert. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Argillite and Chert consists of mineral content and compound content. The mineral content of Argillite includes Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz and mineral content of Chert includes Quartz, Silicon. You can also check out the list of all Sedimentary Rocks. When we have to compare Argillite vs Chert, the texture, color and appearance plays an important role in determining the type of rock. Argillite is available in dark grey to black, pink, red, white colors whereas, Chert is available in black, brown, green, grey, red, white colors. Appearance of Argillite is Rough and Dull and that of Chert is Glassy or Pearly. Properties of rock is another aspect for Argillite vs Chert. The hardness of Argillite is 2-3 and that of Chert is 6.5-7. The types of Argillite are Metamorphic rock whereas types of Chert are Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Argillite is white to grey while that of Chert is white. The specific heat capacity of Argillite is 0.87 kJ/Kg K and that of Chert is 0.74 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Argillite is heat resistant, impact resistant whereas Chert is heat resistant, impact resistant, pressure resistant, wear resistant.