Chalk

Nephelinite

Chalk and Nephelinite

Chalk

Nephelinite

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Definition

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

Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).

History

Origin

Brazil

Discoverer

Unknown

Etymology

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

from French néphéline, from Greek nephelē

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic or Non-Clastic

Aphanitic

Color

Grey, White, Yellow

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Soft

Skeletal

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, 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, Cement Manufacture, Construction Aggregate, for Road Aggregate

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

Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)

Types

Chalk Marl and Marl

Peralkaline Nephelinite

Features

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

Host Rock for Lead

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.

Nephelinite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

Calcite, Clay, Clay Minerals, Quartz, Sand

Clinopyroxene, Nepheline, Plagioclase

Compound Content

Ca, NaCl, CaO

Ca, CaO, Carbon, Cl, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact 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

Chemical Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

16.5

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Flat

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Dull

Vitreous to Metallic

Compressive Strength

5.00 N/mm²35.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.7

Specific Gravity

2.3-2.42.4-2.9

0 8.4

👆🏻

Transparency

Opaque

Density

2.49-2.50 g/cm³2.5-3 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.90 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Japan

Africa

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

Rwanda, Tanzania

Europe

England, France, Germany, Spain, United Kingdom

Others

Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

South America

Colombia

Deposits in Oceania Continent

Australia

Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula

All about Chalk and Nephelinite Properties

Know all about Chalk and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Chalk belongs to Sedimentary Rocks while Nephelinite belongs to Igneous Rocks.Texture of Chalk is Clastic or Non-Clastic whereas that of Nephelinite is Aphanitic. Chalk appears Soft and Nephelinite appears Skeletal. The luster of Chalk is dull while that of Nephelinite is vitreous to metallic. Chalk is available in grey, white, yellow colors whereas Nephelinite is available in black, brown, green, grey, white 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 Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).