Slate

Argillite

Slate and Argillite

Slate

Argillite

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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

Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate

History

Origin

England

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite

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

Texture

Foliated

Clastic, Polished

Color

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

Dark Grey to Black, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Rough and Dull

Uses

Architecture

Interior Uses

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

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

As Dimension Stone

Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

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

Fire resistant, Used to manufracture paperweights and bookends

Types

Phyllite, Schist, and Slate

Metamorphic rock

Features

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

Is one of the oldest rock

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.

An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.

Composition

Mineral Content

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

Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz

Compound Content

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

Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

3-42-3

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Splintery

Conchoidal to Uneven

Streak

Light to dark brown

White to Grey

Porosity

Less Porous

Highly Porous

Luster

Dull

Waxy and Dull

Compressive Strength

30.00 N/mm²-

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

2.6

Specific Gravity

2.65-2.82.56-2.68

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³2.54-2.66 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

Bangladesh, China, India, Russia

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Europe

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

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Others

Arctic

Deposits in Western Continents

North America

USA

South America

Brazil

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

All about Slate and Argillite Properties

Know all about Slate and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Argillite belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Argillite is Clastic, Polished. Slate appears Dull and Argillite appears Rough and Dull. The luster of Slate is dull while that of Argillite is waxy and dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Argillite is available in dark grey to black, pink, 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 Argillite are fire resistant, used to manufracture paperweights and bookends.