Slate

Chert

Slate and Chert

Slate

Chert

Add ⊕

Definition

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism

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

History

Origin

England

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

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

Fine Grained Rock, Opaque Rock

Texture

Foliated

Banded, Rough

Color

Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Glassy or Pearly

Uses

Architecture

Interior Uses

Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads

Decorative Aggregates, Homes

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates

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

Types

Phyllite, Schist, and Slate

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

Features

Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock

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

Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.

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

Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon

Quartz, Silicon

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

3-46.5-7

1 7

👆🏻

Grain Size

Very fine-grained

Fracture

Splintery

Uneven, Splintery or Conchoidal

Streak

Light to dark brown

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Waxy and Dull

Compressive Strength

30.00 N/mm²450.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

1.5

Specific Gravity

2.65-2.82.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.6-2.8 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

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

Africa

Kenya, Morocco, South Africa, Tanzania

Europe

Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom

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

Others

Arctic

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Brazil

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

All about Slate and Chert Properties

Know all about Slate and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Chert belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Chert is Banded, Rough. Slate appears Dull and Chert appears Glassy or Pearly. The luster of Slate is dull while that of Chert is waxy and dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, 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.