Slate

Lignite

Slate and Lignite

Slate

Lignite

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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

Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat

History

Origin

England

France

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

From French, Latin lignum wood + -ite1

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

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

Texture

Foliated

Amorphous, Glassy

Color

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

Black, Brown, Dark Brown, Grey, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Veined or Pebbled

Uses

Architecture

Interior Uses

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

Exterior Uses

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

for Road Aggregate, Steel Production

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

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

Electricity Generation

Types

Phyllite, Schist, and Slate

Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite

Features

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

Generally rough to touch, Helps in production of Heat and Electricity, Used as fossil fuel

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.

Coal formation takes place due to accumulation of plant debris in a swamp environment. The Coal formation process continues, as peat turns into lignite brown or black coal at increasing heat and pressure.

Composition

Mineral Content

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

Compound Content

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

Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur

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, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

3-41

1 7

👆🏻

Grain Size

Very fine-grained

Medium to Fine Coarse Grained

Fracture

Splintery

Conchoidal

Streak

Light to dark brown

Black

Porosity

Less Porous

Highly Porous

Luster

Dull

Dull to Vitreous to Submetallic

Compressive Strength

30.00 N/mm²-

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

Specific Gravity

2.65-2.81.1-1.4

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³800-801 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K1.26 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam

Africa

Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania

Europe

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

Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom

Others

Arctic

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Brazil

Brazil, Chile, Colombia, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, Queensland, Victoria

All about Slate and Lignite Properties

Know all about Slate and Lignite properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Lignite belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Lignite is Amorphous, Glassy. Slate appears Dull and Lignite appears Veined or Pebbled. The luster of Slate is dull while that of Lignite is dull to vitreous to submetallic. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Lignite is available in black, brown, dark brown, grey, light to dark grey 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 Lignite are electricity generation.