Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
Discoverer
Johann Gottlob Lehmann
Tornebohm
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 an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
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
Earthy, Mud-rich, Rough
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
Black, Brown, Green, Grey, White
Durability
Durable
Durable
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, Paving 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 a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Pottery
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Endoskarns
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
Famous Monuments
Jantar Mantar in India
-
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. Skarn 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
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
-
Grain Size
Very fine-grained
Fine Grained
Streak
White
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Dull
Waxy and Dull
Specific Gravity
2.2-2.8
2.86
Transparency
Opaque
Opaque
Density
2.4-2.8 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
South Africa, Western Africa
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
United Kingdom
Deposits in Western Continents
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
Central Australia, Western Australia
All about Shale and Skarn Properties
Know all about Shale and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Skarn belongs to Metamorphic Rocks.Texture of Shale is Clastic, Splintery whereas that of Skarn is Earthy, Mud-rich, Rough. Shale appears Muddy and Skarn appears Dull. The luster of Shale is dull while that of Skarn is waxy and dull. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Skarn is available in black, brown, green, grey, white colors. The commercial uses of Shale are creating artwork, pottery and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).