Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
Migmatite is typically a granitic rock within a metamorphic host rock which is composed of two intermingled but distinguishable components
Origin
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Southern Alps, France
Discoverer
Johann Gottlob Lehmann
Jakob Sederholm
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 the Greek word migma which means a mixture
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Splintery
Foliated
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
Black, Bluish - Grey, Brown, Brown- Black, Dark Greenish - Grey, Dark Grey to Black
Durability
Durable
Durable
Appearance
Muddy
Dull, Banded and Foilated
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Countertops, Flooring, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, As Facing Stone
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
Commercial Uses
Creating Artwork, Pottery
Cemetery Markers, Jewelry, Tombstones, Used to manufracture paperweights and bookends
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Diatexites and Metatexites
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Generally rough to touch, Is one of the oldest rock
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.
Migmatites form by high temperature regional and thermal metamorphism of protolith rocks where rocks melt partially due to high temperature.
Mineral Content
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
Aluminium Oxide, NaCl, CaO, Carbon Dioxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
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Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Medium to Fine Coarse Grained
Porosity
Highly Porous
Very Less Porous
Luster
Dull
Dull to Pearly to Subvitreous
Specific Gravity
2.2-2.8
2.65-2.75
Transparency
Opaque
Opaque
Density
2.4-2.8 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Sweden, Switzerland, Ukraine, United Kingdom
Deposits in Western Continents
North America
USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New South Wales, New Zealand, Queensland, Victoria