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
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Discoverer
Unknown
Unknown
Etymology
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Polished
Clastic or Non-Clastic
Color
Dark Grey to Black, Pink, Red, White
Grey, White, Yellow
Durability
Durable
Durable
Appearance
Rough and Dull
Soft
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Powder
Construction Industry
Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Fire resistant, Used to manufracture paperweights and bookends
Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper
Types
Not Available
Not Available
Features
Is one of the oldest rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
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.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
Ca, NaCl, CaO
Types of Metamorphism
Not Applicable
Not Applicable
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Fine Grained
Very fine-grained
Fracture
Conchoidal to Uneven
Not Available
Streak
White to Grey
White
Porosity
Highly Porous
Highly Porous
Luster
Waxy and Dull
Dull
Cleavage
Slaty
Non-Existent
Specific Gravity
2.56-2.68
2.3-2.4
Transparency
Opaque
Opaque
Density
2.54-2.66 g/cm3
2.49-2.50 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
England, France, Germany, Spain, United Kingdom
Others
Not Yet Found
Not Yet Found
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
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
All about Argillite and Chalk Properties
Know all about Argillite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Argillite and Chalk belong to Sedimentary Rocks.Texture of Argillite is Clastic, Polished whereas that of Chalk is Clastic or Non-Clastic. Argillite appears Rough and Dull and Chalk appears Soft. The luster of Argillite is waxy and dull while that of Chalk is dull. Argillite is available in dark grey to black, pink, red, white colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Argillite are fire resistant, used to manufracture paperweights and bookends and that of Chalk are alumina refineries, creating artwork, drawing on blackboards, gymnasts, athletes and mountain climbers use for grip, in aquifers, paper industry, production of lime, raw material for manufacture of quicklime, slaked lime, soil conditioner, whiting, whiting material in toothpaste, paint and paper.