Slate and Chalk
Definition
Definition
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
History
Origin
England
Unknown
Discoverer
Unknown
Unknown
Etymology
From Old French esclate, from esclat (French éclat)
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Foliated
Clastic or Non-Clastic
Color
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Grey, White, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
Yes
No
Wind Resistant
No
No
Acid Resistant
No
No
Appearance
Dull
Soft
Uses
Architecture
Interior Uses
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
Industry
Construction Industry
As Dimension Stone
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, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates
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
Types
Not Available
Not Available
Features
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Used
Used
Petroglyphs
Used
Used
Figurines
Used
Used
Fossils
Absent
Present
Formation
Formation
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Composition
Mineral Content
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Ca, NaCl, CaO
Transformation
Metamorphism
Yes
No
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Properties
Physical Properties
Hardness
3-4
1
Grain Size
Very fine-grained
Very fine-grained
Fracture
Splintery
Not Available
Streak
Light to dark brown
White
Porosity
Less Porous
Highly Porous
Luster
Dull
Dull
Compressive Strength
30.00 N/mm2
30
Not Available
Cleavage
Slaty
Non-Existent
Toughness
1.2
1
Specific Gravity
2.65-2.8
2.3-2.4
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm3
2.49-2.50 g/cm3
Thermal Properties
Specific Heat Capacity
0.76 kJ/Kg K
17
0.90 kJ/Kg K
12
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Turkey
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Not Yet Found
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
England, France, Germany, Spain, United Kingdom
Others
Arctic
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Brazil
Colombia
Deposits in Oceania Continent
Australia
Not Yet Found
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
All about Slate and Chalk Properties
Know all about Slate and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Chalk belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Chalk is Clastic or Non-Clastic. Slate appears Dull and Chalk appears Soft. The luster of Slate and Chalk is dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates 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.
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