Chert

Dunite

Chert and Dunite

Chert

Dunite

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Definition

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

Dunite is a green to brownish coarse-grained igneous rock mainly consisting of olivine

History

Origin

New Zealand

Discoverer

Unknown

Ferdinand von Hochstetter

Etymology

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

From the name of Dun Mountain, New Zealand, + -ite1

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Banded, Rough

Phaneritic

Color

Black, Brown, Green, Grey, Red, White

Dark Greenish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

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

Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds

Types

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

Dunite

Features

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

Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

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.

Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. It can be formed in two ways.

Composition

Mineral Content

Quartz, Silicon

Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene

Compound Content

Silicon Dioxide

Ca, CaO, Fe, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Coastal Erosion, Glacier Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.5-73.5-4

1 7

👆🏻

Grain Size

Very fine-grained

Coarse Grained

Fracture

Uneven, Splintery or Conchoidal

Irregular

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Waxy and Dull

Shiny

Compressive Strength

450.00 N/mm²107.55 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.5

2.1

Specific Gravity

2.5-2.83-3.01

0 8.4

👆🏻

Transparency

Translucent to Opaque

Density

2.7 g/cm³2.84-2.85 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K1.25 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey

Africa

Kenya, Morocco, South Africa, Tanzania

Morocco, South Africa

Europe

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

Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, USA

South America

Bolivia, Brazil

Argentina, Brazil, Colombia, Ecuador, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

New Zealand, Western Australia

All about Chert and Dunite Properties

Know all about Chert and Dunite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Dunite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Dunite is Phaneritic. Chert appears Glassy or Pearly and Dunite appears Rough and Shiny. The luster of Chert is waxy and dull while that of Dunite is shiny. Chert is available in black, brown, green, grey, red, white colors whereas Dunite is available in dark greenish - grey colors. The commercial uses of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms and that of Dunite are creating artwork, gemstone, jewelry, source of chromite, platinum, nickel and garnet, source of diamonds.