Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
Johann Gottlob Lehmann
Unknown
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 pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Splintery
Quench
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
Black, Brown, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Muddy
Dull and Soft
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments
Commercial Uses
Creating Artwork, Pottery
Creating Artwork, Gemstone
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Cataclastic rock
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Host Rock for Lead
Archaeological Significance
Famous Monuments
Jantar Mantar in India
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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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
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Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
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Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
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Grain Size
Very fine-grained
Very fine-grained
Streak
White
Light to dark brown
Porosity
Highly Porous
Less Porous
Specific Gravity
2.2-2.8
2.46-2.86
Transparency
Opaque
Transparent to Translucent
Density
2.4-2.8 g/cm3
2.7-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
South Korea
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Western Africa
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Great Britain, Switzerland
Deposits in Western Continents
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
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Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
Central Australia, Western Australia
All about Shale and Pseudotachylite Properties
Know all about Shale and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Shale is Clastic, Splintery whereas that of Pseudotachylite is Quench. Shale appears Muddy and Pseudotachylite appears Dull and Soft. The luster of Shale is dull while that of Pseudotachylite is vitreous. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Shale are creating artwork, pottery and that of Pseudotachylite are creating artwork, gemstone.