Slate

Chalk

Slate and Chalk

Slate

Chalk

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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

Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers

History

Origin

England

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone

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 or Non-Clastic

Color

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

Grey, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Soft

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, As Facing Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Powder

Industry

Construction Industry

As Dimension Stone

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium

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

Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper

Types

Phyllite, Schist, and Slate

Chalk Marl and Marl

Features

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

Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained 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.

Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.

Composition

Mineral Content

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

Calcite, Clay, Clay Minerals, Quartz, Sand

Compound Content

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

Ca, NaCl, CaO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

3-41

1 7

👆🏻

Grain Size

Very fine-grained

Fracture

Splintery

Streak

Light to dark brown

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Compressive Strength

30.00 N/mm²5.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

Specific Gravity

2.65-2.82.3-2.4

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³2.49-2.50 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.90 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

Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam

Africa

Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe

Europe

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

England, France, Germany, Spain, United Kingdom

Others

Arctic

Deposits in Western Continents

North America

USA

Canada, USA

South America

Brazil

Colombia

Deposits in Oceania Continent

Australia

Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula

All about Slate and Chalk Properties

Know all about Slate and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Chalk belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Chalk is Clastic or Non-Clastic. Slate appears Dull and Chalk appears Soft. The luster of Slate and Chalk is dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Chalk is available in grey, white, yellow 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 Chalk are alumina refineries, creating artwork, drawing on blackboards, gymnasts, athletes and mountain climbers use for grip, in aquifers, paper industry, production of lime, raw material for manufacture of quicklime, slaked lime, soil conditioner, whiting, whiting material in toothpaste, paint and paper.