Chert

Essexite

Chert and Essexite

Chert

Essexite

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1 Definition

1.1 Definition

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

Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous Rock

1.2 History

1.2.1 Origin

Unknown

USA

1.2.2 Discoverer

Unknown

1.3 Etymology

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

From the locality in Essex County, Massachusetts,US

1.4 Class

Sedimentary Rocks

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Not Applicable

Plutonic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Banded, Rough

Granular

2.2 Color

Black, Brown, Green, Grey, Red, White

Dark Grey to Black

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Glassy or Pearly

Banded

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Homes, Interior Decoration

3.1.2 Exterior Uses

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

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

3.4 Other Uses

3.4.1 Commercial Uses

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

Cemetery Markers, Commemorative Tablets, Jewelry, Sea Defence, Tombstones

4 Types

4.1 Types

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

Not Available

4.2 Features

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

Is one of the oldest rock, Smooth to touch

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

4.3.3 Sculpture

Not Yet Used

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Not Used

4.3.6 Petroglyphs

Not Used

4.3.7 Figurines

Not Yet Used

Used

4.4 Fossils

Present

Absent

5 Formation

5.1 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.

Essexite is a type of igneous rock, which is usually dark grey to black plutonic rock. For the formation of essexite, suitable magma with exact composition of K, Ba, Rb, Cs, Sr should be produced.

5.2 Composition

5.2.1 Mineral Content

Quartz, Silicon

Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene

5.2.2 Compound Content

Silicon Dioxide

Aluminium Oxide, Ba, Ca, Cs, Potassium, Rb, Sodium, Sr

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Not Applicable

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Not Applicable

Biological Weathering, Chemical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion

Coastal Erosion, Glacier Erosion, Water Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.5-77

1 7

6.1.2 Grain Size

Very fine-grained

Fine Grained

6.1.3 Fracture

Uneven, Splintery or Conchoidal

Conchoidal

6.1.4 Streak

White

Black

6.1.5 Porosity

Highly Porous

6.1.6 Luster

Waxy and Dull

Not Available

6.1.7 Compressive Strength

450.00 N/mm²NA

0.15 450

6.1.8 Cleavage

Non-Existent

Not Available

6.1.9 Toughness

1.5

1.6

6.1.10 Specific Gravity

2.5-2.8Not Available

0 8.4

6.1.11 Transparency

Translucent to Opaque

Opaque

6.1.12 Density

2.7 g/cm³Not Available

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.74 kJ/Kg KNA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Impact Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

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

India, Russia

7.1.2 Africa

Kenya, Morocco, South Africa, Tanzania

South Africa

7.1.3 Europe

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

Germany, Greece, Italy, Scotland, Turkey

7.1.4 Others

Greenland, Mid-Atlantic Ridge

Greenland

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Canada, USA

7.2.2 South America

Bolivia, Brazil

Brazil, Colombia, Venezuela

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, Queensland, South Australia, Western Australia

New Zealand, Queensland

All about Chert and Essexite Properties

Know all about Chert and Essexite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Essexite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Essexite is Granular. Chert appears Glassy or Pearly and Essexite appears Banded. The luster of Chert is waxy and dull while that of Essexite is not available. Chert is available in black, brown, green, grey, red, white colors whereas Essexite is available in dark grey to black 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 Essexite are cemetery markers, commemorative tablets, jewelry, sea defence, tombstones.