Nephelinite

Chalk

Nephelinite and Chalk

Nephelinite

Chalk

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Definition

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

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

History

Origin

Brazil

Discoverer

Unknown

Etymology

from French néphéline, from Greek nephelē

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

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Aphanitic

Clastic or Non-Clastic

Color

Black, Brown, Green, Grey, White

Grey, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Skeletal

Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Powder

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate

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

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

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

Peralkaline Nephelinite

Chalk Marl and Marl

Features

Host Rock for Lead

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

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.

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

Composition

Mineral Content

Clinopyroxene, Nepheline, Plagioclase

Calcite, Clay, Clay Minerals, Quartz, Sand

Compound Content

Ca, CaO, Carbon, Cl, MgO

Ca, NaCl, CaO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.51

1 7

👆🏻

Grain Size

Fine Grained

Very fine-grained

Fracture

Flat

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Vitreous to Metallic

Dull

Compressive Strength

35.00 N/mm²5.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.7

Specific Gravity

2.4-2.92.3-2.4

0 8.4

👆🏻

Transparency

Opaque

Density

2.5-3 g/cm³2.49-2.50 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.90 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan

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

Africa

Rwanda, Tanzania

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

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 Nephelinite and Chalk Properties

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