Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
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
History
Origin
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England
Discoverer
Johann Gottlob Lehmann
Abraham Gottlob Werner
Etymology
From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
From Old French esclate, from esclat (French éclat)
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Splintery
Foliated
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Maintenance
More
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Muddy
Dull
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
As Dimension Stone
Medical Industry
-
-
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Creating Artwork, Pottery
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
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Phyllite, Schist, and Slate
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Archaeological Significance
Monuments
-
-
Famous Monuments
Jantar Mantar in India
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Sculpture
-
-
Famous Sculptures
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-
Pictographs
-
-
Petroglyphs
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-
Figurines
-
-
Fossils
Present
Absent
Formation
Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Composition
Mineral Content
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
33-4
1
7
👆🏻
Grain Size
Very fine-grained
Very fine-grained
Fracture
-
Splintery
Streak
White
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Dull
Dull
Compressive Strength
95.00 N/mm230.00 N/mm2
0.15
450
👆🏻
Cleavage
Slaty
Slaty
Toughness
2.6
1.2
Specific Gravity
2.2-2.82.65-2.8
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.4-2.8 g/cm32.6-2.8 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.39 kJ/Kg K0.76 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Turkey
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
-
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Others
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Arctic
Deposits in Western Continents
North America
USA
USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
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