Basalt

Chert

Basalt and Chert

Basalt

Chert

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Definition

Basalt is a common extrusive igneous rock formed by the rapid cooling of basaltic lava exposed at or very near the surface of Earth

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

History

Origin

Egypt

Discoverer

Georgius Agricola

Unknown

Etymology

From Late Latin Basaltes (variant of basanites ), very hard stone, which was imported from Ancient Greek Basanites

From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Banded, Rough

Color

Black, Brown, Light to Dark Grey

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Glassy or Pearly

Uses

Architecture

Interior Uses

Floor Tiles, Homes, Hotels, Kitchens

Decorative Aggregates, Homes

Exterior Uses

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

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

Other Architectural Uses

Curbing, Whetstones

Curbing

Industry

Construction Industry

Arrowheads, As Dimension Stone, Cobblestones, Cutting Tool, Rail Track Ballast, Roadstone

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Monuments

Other Uses

Commercial Uses

An Oil and Gas Reservoir, Commemorative Tablets, Creating Artwork, Used in aquariums

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

Types

Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

Features

Has High structural resistance against erosion and climate, Very fine grained rock

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Archaeological Significance

Monuments

Famous Monuments

Easter Island in the Polynesian Triangle, Pacific Ocean, Gateway of India in Mumbai, India, Gol Gumbaz in Karnataka, India

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

Basalt forms when lava reaches the Earth's surface near an active volcano. The temperature of lava is between 1100 to 1250° C when it gets to the surface.

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Quartz, Silicon

Compound Content

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

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

66.5-7

1 7

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Grain Size

Fine Grained

Very fine-grained

Fracture

Conchoidal

Uneven, Splintery or Conchoidal

Streak

White to Grey

White

Porosity

Less Porous

Highly Porous

Luster

Waxy and Dull

Compressive Strength

37.40 N/mm²450.00 N/mm²

0.15 450

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Cleavage

Toughness

2.3

1.5

Specific Gravity

2.8-32.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.9-3.1 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

South Africa

Kenya, Morocco, South Africa, Tanzania

Europe

Iceland

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, USA

Canada, Mexico, USA

South America

Brazil

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

All about Basalt and Chert Properties

Know all about Basalt and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Basalt belongs to Igneous Rocks while Chert belongs to Sedimentary Rocks.Texture of Basalt is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Chert is Banded, Rough. Basalt appears Dull and Soft and Chert appears Glassy or Pearly. The luster of Basalt is while that of Chert is waxy and dull. Basalt is available in black, brown, light to dark grey colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Basalt are an oil and gas reservoir, commemorative tablets, creating artwork, used in aquariums and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.