Chalk

Slate

Chalk and Slate

Chalk

Slate

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Definition

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

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

History

Origin

England

Discoverer

Unknown

Abraham Gottlob Werner

Etymology

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

From Old French esclate, from esclat (French éclat)

Class

Sedimentary Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic or Non-Clastic

Foliated

Color

Grey, White, Yellow

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Soft

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

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

Exterior Uses

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

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

Other Architectural Uses

Powder

Curbing

Industry

Construction Industry

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

As Dimension Stone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

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

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

Types

Chalk Marl and Marl

Phyllite, Schist, and Slate

Features

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

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

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

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

Composition

Mineral Content

Calcite, Clay, Clay Minerals, Quartz, Sand

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

Compound Content

Ca, NaCl, CaO

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

13-4

1 7

👆🏻

Grain Size

Very fine-grained

Fracture

Splintery

Streak

White

Light to dark brown

Porosity

Highly Porous

Less Porous

Luster

Dull

Compressive Strength

5.00 N/mm²30.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

Specific Gravity

2.3-2.42.65-2.8

0 8.4

👆🏻

Transparency

Opaque

Density

2.49-2.50 g/cm³2.6-2.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.90 kJ/Kg K0.76 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Turkey

Africa

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

Europe

England, France, Germany, Spain, United Kingdom

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

Others

Arctic

Deposits in Western Continents

North America

Canada, USA

USA

South America

Colombia

Brazil

Deposits in Oceania Continent

Australia

Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula

All about Chalk and Slate Properties

Know all about Chalk and Slate properties here. All properties of rocks are important as they define the type of rock and its application. Chalk belongs to Sedimentary Rocks while Slate belongs to Metamorphic Rocks.Texture of Chalk is Clastic or Non-Clastic whereas that of Slate is Foliated. Chalk appears Soft and Slate appears Dull. The luster of Chalk and Slate is dull. Chalk is available in grey, white, yellow colors whereas Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors. The commercial uses 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 and that 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.