Tephrite

Obsidian

Tephrite and Obsidian

Tephrite

Obsidian

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1 Definition

1.1 Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth

1.2 History

1.2.1 Origin

Germany

Ethiopia

1.2.2 Discoverer

Van Tooren

Obsius

1.3 Etymology

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

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

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

Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

Glassy

2.2 Color

Black, Brown, Colourless, Green, Grey, White

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

81% Igneous Rocks Rocks have it !

✔ ✘

81% Igneous Rocks Rocks have it !

2.4.2 Scratch Resistant

✔ ✘

86% Igneous Rocks Rocks have it !

✔ ✘

86% Igneous Rocks Rocks have it !

2.4.3 Stain Resistant

✔ ✘

66% Igneous Rocks Rocks have it !

✔ ✘

66% Igneous Rocks Rocks have it !

2.4.4 Wind Resistant

✔ ✘

49% Igneous Rocks Rocks have it !

✔ ✘

49% Igneous Rocks Rocks have it !

2.4.5 Acid Resistant

✔ ✘

48% Igneous Rocks Rocks have it !

✔ ✘

48% Igneous Rocks Rocks have it !

2.5 Appearance

Vesicular

Shiny

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

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

Garden Decoration

3.1.3 Other Architectural Uses

Curbing

Not Yet Used

3.2 Industry

3.2.1 Construction Industry

Landscaping

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

3.2.2 Medical Industry

Not Yet Used

Surgery

3.3 Antiquity Uses

Artifacts, Sculpture

Artifacts, Jewellery

3.4 Other Uses

3.4.1 Commercial Uses

Production of Lime, Soil Conditioner

Creating Artwork, Mirror, Used in aquariums

4 Types

4.1 Types

Not Available

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

4.2 Features

Host Rock for Lead

Blocks negativity, Helps to protect against depression

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

4.3.2 Famous Monuments

Not Applicable

4.3.3 Sculpture

Used

Not Yet Used

4.3.4 Famous Sculptures

Data Not Available

Not Applicable

4.3.5 Pictographs

Not Used

Used

4.3.6 Petroglyphs

Not Used

Used

4.3.7 Figurines

Used

Not Yet Used

4.4 Fossils

Absent

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.

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

5.2 Composition

5.2.1 Mineral Content

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Not Available

5.2.2 Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

97% Igneous Rocks Rocks have it !

✔ ✘

97% Igneous Rocks Rocks have it !

5.3.2 Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

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99% Igneous Rocks Rocks have it !

✔ ✘

99% Igneous Rocks Rocks have it !

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

92% Igneous Rocks Rocks have it !

✔ ✘

92% Igneous Rocks Rocks have it !

5.3.6 Types of Erosion

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

Chemical Erosion, Coastal Erosion, Glacier Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.5

5-5.5

6.1.2 Grain Size

Medium to Fine Coarse Grained

Not Applicable

6.1.3 Fracture

Uneven

Conchoidal

6.1.4 Streak

Bluish Black

White

6.1.5 Porosity

Very Less Porous

6.1.6 Luster

Subvitreous to Dull

Vitreous

6.1.7 Compressive Strength

What Is Flint

⊕

▶

▼

90.00 N/mm²

Rank: 22 (Overall)▶

0.15 N/mm²

Rank: 33 (Overall)▶

▲

What Is Obsidian

⊕

▶

175 (What Is Grani..)

◀ ▶ ADD ⊕

6.1.8 Cleavage

Crenulation and Pervasive

Non-Existent

6.1.9 Toughness

2.4

Not Available

6.1.10 Specific Gravity

2.86

2.6-2.7

6.1.11 Transparency

Opaque

Translucent

6.1.12 Density

2.8-2.9 g/cm³

2.6 g/cm³

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

What Is Banded ..

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▶

▼

0.92 kJ/Kg K

Rank: 10 (Overall)▶

0.92 kJ/Kg K

Rank: 10 (Overall)▶

▲

What Is Granulite

⊕

▶

1.09 (What Is Trave..)

◀ ▶ ADD ⊕

6.2.2 Resistance

Heat Resistant, Impact Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

Afghanistan, Indonesia, Japan, Russia

7.1.2 Africa

Namibia, Uganda

Kenya

7.1.3 Europe

Germany, Hungary, Italy, Portugal, Spain

Greece, Hungary, Iceland, Italy, Turkey

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

USA

Canada, Mexico, USA

7.2.2 South America

Not Yet Found

Argentina, Chile, Ecuador, Peru

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, Western Australia

New Zealand

All about Tephrite and Obsidian Properties

Know all about Tephrite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite and Obsidian belong to Igneous Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Obsidian is Glassy. Tephrite appears Vesicular and Obsidian appears Shiny. The luster of Tephrite is subvitreous to dull while that of Obsidian is vitreous. Tephrite is available in black, brown, colourless, green, grey, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Obsidian are creating artwork, mirror, used in aquariums.