Definition
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Discoverer
Unknown
Unknown
Etymology
From French schiste, Greek skhistos i.e. split
From Greek pikros bitter + -ite, 19th century
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Foliated, Platy
Earthy, Rough
Color
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Black, Brown, Green, Grey, Pink, White, Yellow
Durability
Durable
Durable
Appearance
Layered and Shiny
Rough and Shiny
Interior Uses
Decorative Aggregates, Floor Tiles, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
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Curbing
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Used in aquariums, Writing Slates
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Types
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Oceanite
Features
Easily splits into thin plates, Smooth to touch
Host Rock for Lead
Archaeological Significance
Formation
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
Picrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Biotite, Olivine, Plagioclase, Pyrrhotite
Compound Content
CaO, Carbon Dioxide, MgO
Al, CaO, Carbon Dioxide, Mg, MgO
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Uneven
Streak
White
White, Greenish White or Grey
Porosity
Highly Porous
Less Porous
Luster
Shiny
Subvitreous to Dull
Specific Gravity
2.5-2.9
2.75-2.92
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
1.5-2.5 g/cm3
Resistance
Impact Resistant, Pressure Resistant, Water Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
India, Russia
Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
South Africa
Europe
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Iceland
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, USA
South America
Brazil, Colombia, Guyana
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland
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All about Schist and Picrite Properties
Know all about Schist and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Schist belongs to Metamorphic Rocks while Picrite belongs to Igneous Rocks.Texture of Schist is Foliated, Platy whereas that of Picrite is Earthy, Rough. Schist appears Layered and Shiny and Picrite appears Rough and Shiny. The luster of Schist is shiny while that of Picrite is subvitreous to dull. Schist is available in black, blue, brown, dark brown, green, grey, silver colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Schist are used in aquariums, writing slates and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).