Picrite

Chalk

Picrite and Chalk

Picrite

Chalk

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Definition

Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine

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

History

Origin

Hawaii Islands

Discoverer

Unknown

Etymology

From Greek pikros bitter + -ite, 19th century

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

Fine Grained Rock, Opaque Rock

Texture

Earthy, Rough

Clastic or Non-Clastic

Color

Black, Brown, Green, Grey, Pink, White, Yellow

Grey, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Rough and Shiny

Soft

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Homes, Interior Decoration

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 a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.

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

As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, 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

Oceanite

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

Picrite 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

Biotite, Olivine, Plagioclase, Pyrrhotite

Calcite, Clay, Clay Minerals, Quartz, Sand

Compound Content

Al, CaO, Carbon Dioxide, Mg, MgO

Ca, NaCl, CaO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.81

1 7

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Grain Size

Fine Grained

Very fine-grained

Fracture

Uneven

Streak

White, Greenish White or Grey

White

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Dull

Compressive Strength

189.00 N/mm²5.00 N/mm²

0.15 450

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Cleavage

Toughness

2.1

Specific Gravity

2.75-2.922.3-2.4

0 8.4

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Transparency

Opaque

Density

1.5-2.5 g/cm³2.49-2.50 g/cm³

0 1400

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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

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 Picrite and Chalk Properties

Know all about Picrite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Picrite belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Picrite is Earthy, Rough whereas that of Chalk is Clastic or Non-Clastic. Picrite appears Rough and Shiny and Chalk appears Soft. The luster of Picrite is subvitreous to dull while that of Chalk is dull. Picrite and Chalk are available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, 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.