Schist

Picrite

Schist and Picrite

Schist

Picrite

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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

History

Origin

Hawaii Islands

Discoverer

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

Family

Group

Volcanic

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered and Shiny

Rough and Shiny

Uses

Architecture

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

Curbing

Industry

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.

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture

Other Uses

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

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Composition

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

3.5-46.8

1 7

👆🏻

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

Compressive Strength

150.00 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.5

2.1

Specific Gravity

2.5-2.92.75-2.92

0 8.4

👆🏻

Transparency

Opaque

Density

2.8-2.9 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.70 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Impact Resistant, Pressure Resistant, Water Resistant

Heat Resistant

Reserves

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

Others

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

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).