Chert

Ignimbrite

Chert and Ignimbrite

Chert

Ignimbrite

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Definition

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

Ignimbrite is a volcanic rock consisting mainly of pumice fragments, formed by the consolidation of material deposited by pyroclastic flows

History

Origin

New Zealand

Discoverer

Unknown

Patrick Marshall

Etymology

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

From Latin ignis fire + imber, imbr- shower of rain, storm cloud + -ite

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Banded, Rough

Aphanitic

Color

Black, Brown, Green, Grey, Red, White

Beige, Black, Brown, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Dull, Vesicular and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Building houses or walls, Construction Aggregate

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

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

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

Pyroclastic rock

Features

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

Always found as volcanic pipes over deep continental crust

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.

Ignimbrites are formed from very poorly sorted mixture of volcanic ash or tuff and pumice lapilli, commonly with scattered lithic fragments.

Composition

Mineral Content

Quartz, Silicon

Apatite, Biotite, Calcite, Chlorite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz

Compound Content

Silicon Dioxide

Ca, NaCl

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion

Properties

Physical Properties

Hardness

6.5-74-6

1 7

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Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven, Splintery or Conchoidal

Uneven

Streak

White

Porosity

Highly Porous

Luster

Waxy and Dull

Vitreous to Dull

Compressive Strength

450.00 N/mm²243.80 N/mm²

0.15 450

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Cleavage

Toughness

1.5

Specific Gravity

2.5-2.82.73

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³1-1.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.20 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen

Africa

Kenya, Morocco, South Africa, Tanzania

Cameroon, Cape Verde, Chad, Djibouti, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Tanzania, Uganda

Europe

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

France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Antarctica, Hawaii Islands

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, Costa Rica, Panama, USA

South America

Bolivia, Brazil

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

Central Australia, Western Australia

All about Chert and Ignimbrite Properties

Know all about Chert and Ignimbrite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Ignimbrite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Ignimbrite is Aphanitic. Chert appears Glassy or Pearly and Ignimbrite appears Dull, Vesicular and Foilated. The luster of Chert is waxy and dull while that of Ignimbrite is vitreous to dull. Chert is available in black, brown, green, grey, red, white colors whereas Ignimbrite is available in beige, black, brown, grey, pink, white 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 Ignimbrite are cemetery markers, commemorative tablets, creating artwork.