Tephrite

Chert

Tephrite and Chert

Tephrite

Chert

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1 Definition

1.1 Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

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

1.2 History

1.2.1 Origin

Germany

Unknown

1.2.2 Discoverer

Van Tooren

Unknown

1.3 Etymology

From Greek tephra, ashes from Indo-European base, to burn

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

1.4 Class

Igneous Rocks

Sedimentary Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

Not Applicable

1.6 Other Categories

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

Banded, Rough

2.2 Color

Black, Brown, Colourless, Green, Grey, White

Black, Brown, Green, Grey, Red, White

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

Vesicular

Glassy or Pearly

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Homes

3.1.2 Exterior Uses

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

Landscaping

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments

3.4 Other Uses

3.4.1 Commercial Uses

Production of Lime, Soil Conditioner

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

4 Types

4.1 Types

Not Available

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

4.2 Features

Host Rock for Lead

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

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

Used

4.3.2 Famous Monuments

Not Applicable

Data Not Available

4.3.3 Sculpture

Used

Not Yet Used

4.3.4 Famous Sculptures

Data Not Available

Not Applicable

4.3.5 Pictographs

Not Used

4.3.6 Petroglyphs

Not Used

4.3.7 Figurines

Used

Not Yet Used

4.4 Fossils

Absent

Present

5 Formation

5.1 Formation

Tephrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

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.

5.2 Composition

5.2.1 Mineral Content

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Quartz, Silicon

5.2.2 Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Silicon Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Not Applicable

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Not Applicable

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

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

Chemical Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.56.5-7

1 7

6.1.2 Grain Size

Medium to Fine Coarse Grained

Very fine-grained

6.1.3 Fracture

Uneven

Uneven, Splintery or Conchoidal

6.1.4 Streak

Bluish Black

White

6.1.5 Porosity

Very Less Porous

Highly Porous

6.1.6 Luster

Subvitreous to Dull

Waxy and Dull

6.1.7 Compressive Strength

90.00 N/mm²450.00 N/mm²

0.15 450

6.1.8 Cleavage

Crenulation and Pervasive

Non-Existent

6.1.9 Toughness

2.4

1.5

6.1.10 Specific Gravity

2.862.5-2.8

0 8.4

6.1.11 Transparency

Opaque

Translucent to Opaque

6.1.12 Density

2.8-2.9 g/cm³2.7 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

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

7.1.2 Africa

Namibia, Uganda

Kenya, Morocco, South Africa, Tanzania

7.1.3 Europe

Germany, Hungary, Italy, Portugal, Spain

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

7.1.4 Others

Not Yet Found

Greenland, Mid-Atlantic Ridge

7.2 Deposits in Western Continents

7.2.1 North America

USA

Canada, Mexico, USA

7.2.2 South America

Not Yet Found

Bolivia, Brazil

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, Western Australia

New South Wales, Queensland, South Australia, Western Australia

All about Tephrite and Chert Properties

Know all about Tephrite and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Chert belongs to Sedimentary Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Chert is Banded, Rough. Tephrite appears Vesicular and Chert appears Glassy or Pearly. The luster of Tephrite is subvitreous to dull while that of Chert is waxy and dull. Tephrite is available in black, brown, colourless, green, grey, white colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.