Schist

Chert

Schist and Chert

Schist

Chert

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Definition

Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

History

Origin

Discoverer

Unknown

Etymology

From French schiste, Greek skhistos i.e. split

From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Foliated, Platy

Banded, Rough

Color

Black, Blue, Brown, Dark Brown, Green, Grey, Silver

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered and Shiny

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments

Other Uses

Commercial Uses

Used in aquariums, Writing Slates

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

Types

Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

Features

Easily splits into thin plates, Smooth to touch

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

Composition

Mineral Content

Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc

Quartz, Silicon

Compound Content

CaO, Carbon Dioxide, MgO

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

3.5-46.5-7

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Very fine-grained

Fracture

Conchoidal

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Shiny

Waxy and Dull

Compressive Strength

150.00 N/mm²450.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.5

Specific Gravity

2.5-2.92.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.8-2.9 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.70 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Impact Resistant, Pressure Resistant, Water Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam

China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

Egypt, Ethiopia, Morocco, Nigeria, South Africa

Kenya, Morocco, South Africa, Tanzania

Europe

Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Costa Rica, Cuba, Mexico, Panama, USA

Canada, Mexico, USA

South America

Brazil, Colombia, Guyana

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland

New South Wales, Queensland, South Australia, Western Australia

All about Schist and Chert Properties

Know all about Schist and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Schist belongs to Metamorphic Rocks while Chert belongs to Sedimentary Rocks.Texture of Schist is Foliated, Platy whereas that of Chert is Banded, Rough. Schist appears Layered and Shiny and Chert appears Glassy or Pearly. The luster of Schist is shiny while that of Chert is waxy and dull. Schist is available in black, blue, brown, dark brown, green, grey, silver colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Schist are used in aquariums, writing slates and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.