Chert

Pumice

Chert and Pumice

Chert

Pumice

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Definition

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

Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals

History

Origin

Spain

Discoverer

Unknown

Etymology

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

From Old French pomis, from a Latin dialect variant of pumex

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

Vesicular

Color

Black, Brown, Green, Grey, Red, White

Beige, Grey, Light Green, Light Grey, Pink, White, Yellow- grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Flooring, Homes, 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

Curbing, Powder

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks

Medical Industry

As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics

Antiquity Uses

Artifacts, Monuments

Artifacts

Other Uses

Commercial Uses

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

As a traction material on snow-covered roads, As an abrasive in pencil erasers, Fine abrasive used for polishing, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Used in aquariums

Types

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

Scoria

Features

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

Host Rock for Lead

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.

Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.

Composition

Mineral Content

Quartz, Silicon

Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica

Compound Content

Silicon Dioxide

Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Impact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

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

Properties

Physical Properties

Hardness

6.5-76

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven, Splintery or Conchoidal

Planar

Streak

White

White, Greenish White or Grey

Porosity

Highly Porous

Luster

Waxy and Dull

Earthy

Compressive Strength

450.00 N/mm²51.20 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.5

Specific Gravity

2.5-2.82.86

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³0.25-0.3 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya, Morocco, South Africa, Tanzania

Ethiopia, Kenya, Tanzania

Europe

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

Greece, Hungary, Iceland, Italy, Turkey

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA

South America

Bolivia, Brazil

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

New Zealand, Western Australia

All about Chert and Pumice Properties

Know all about Chert and Pumice properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Pumice belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Pumice is Vesicular. Chert appears Glassy or Pearly and Pumice appears Vesicular. The luster of Chert is waxy and dull while that of Pumice is earthy. Chert is available in black, brown, green, grey, red, white colors whereas Pumice is available in beige, grey, light green, light grey, pink, white, yellow- 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 Pumice are as a traction material on snow-covered roads, as an abrasive in pencil erasers, fine abrasive used for polishing, manufacture of soap, solvents, dyes, plastics and fibres, used in aquariums.