Variolite

Chalk

Variolite and Chalk

Variolite

Chalk

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Definition

Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance

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

History

Origin

France

Discoverer

Unknown

Etymology

From Latin varius, speckled, variegated

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

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Clastic or Non-Clastic

Color

Black, Brown, Light to Dark Grey

Grey, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Soft

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

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

Other Architectural Uses

Curbing

Powder

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

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

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

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

Metamorphic rock

Chalk Marl and Marl

Features

Has High structural resistance against erosion and climate, 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

Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.

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

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Calcite, Clay, Clay Minerals, Quartz, Sand

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Ca, NaCl, CaO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

1 7

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Grain Size

Very fine-grained

Fracture

Conchoidal

Streak

White to Grey

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Compressive Strength

37.50 N/mm²5.00 N/mm²

0.15 450

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Cleavage

Toughness

2.3

Specific Gravity

2.8-32.3-2.4

0 8.4

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Transparency

Opaque

Density

2.9-3.1 g/cm³2.49-2.50 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.90 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

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

Africa

South Africa

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

Europe

Iceland

England, France, Germany, Spain, United Kingdom

Others

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Colombia

Deposits in Oceania Continent

Australia

Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula

All about Variolite and Chalk Properties

Know all about Variolite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Chalk is Clastic or Non-Clastic. Variolite appears Dull and Soft and Chalk appears Soft. The luster of Variolite is while that of Chalk is dull. Variolite is available in black, brown, light to dark grey colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Variolite are cemetery markers, creating artwork 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.