Chert

Gritstone

Chert and Gritstone

Chert

Gritstone

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Definition

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

Gritstone or grit is a hard, coarse-grained, siliceous sandstone

History

Origin

Pennines, England

Discoverer

Unknown

J.J. Ferber

Etymology

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

From Grit + Stone

Class

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Banded, Rough

Earthy

Color

Black, Brown, Green, Grey, Red, White

Beige, Black, Brown, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Layered and Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Countertops, Decorative Aggregates, 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

Construction Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

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

An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO), Tombstones

Types

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

Sedimentary rock

Features

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

Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

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.

Gritstone is a type of sedimentary rock which was formed on the floors of wide river deltas where the grit deposits were laid down, with every tide or flood dumping another layer of sediment.

Composition

Mineral Content

Quartz, Silicon

Calcite, Clay Minerals, Feldspar, Micas, Quartz

Compound Content

Silicon Dioxide

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion

Properties

Physical Properties

Hardness

6.5-76-7

1 7

👆🏻

Grain Size

Very fine-grained

Coarse Grained

Fracture

Uneven, Splintery or Conchoidal

Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Waxy and Dull

Dull

Compressive Strength

450.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.5

Specific Gravity

2.5-2.82.250

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³2.2 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

Africa

Kenya, Morocco, South Africa, Tanzania

Namibia, Nigeria, South Africa

Europe

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

Austria, Denmark, Germany, Great Britain, Netherlands, Poland, Sweden, Switzerland, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Greenland

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, USA

South America

Bolivia, Brazil

Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

New South Wales, New Zealand, Western Australia

All about Chert and Gritstone Properties

Know all about Chert and Gritstone properties here. All properties of rocks are important as they define the type of rock and its application. Chert and Gritstone belong to Sedimentary Rocks.Texture of Chert is Banded, Rough whereas that of Gritstone is Earthy. Chert appears Glassy or Pearly and Gritstone appears Layered and Foliated. The luster of Chert is waxy and dull while that of Gritstone is dull. Chert is available in black, brown, green, grey, red, white colors whereas Gritstone is available in beige, black, brown, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow 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 Gritstone are an oil and gas reservoir, as a feed additive for livestock, gemstone, metallurgical flux, production of lime, soil conditioner, source of magnesia (mgo), tombstones.