Obsidian

Tephrite

Obsidian and Tephrite

Obsidian

Tephrite

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1 Definition

1.1 Definition

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

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

1.2 History

1.2.1 Origin

Ethiopia

Germany

1.2.2 Discoverer

Obsius

Van Tooren

1.3 Etymology

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

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

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Opaque Rock

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

2 Texture

2.1 Texture

Glassy

Aphanitic to Porphyritic

2.2 Color

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

Black, Brown, Colourless, Green, Grey, White

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

Shiny

Vesicular

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration

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

3.1.3 Other Architectural Uses

Not Yet Used

Curbing

3.2 Industry

3.2.1 Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Landscaping

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Artifacts, Sculpture

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Production of Lime, Soil Conditioner

4 Types

4.1 Types

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

Not Available

4.2 Features

Blocks negativity, Helps to protect against depression

Host Rock for Lead

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

4.3.2 Famous Monuments

Not Applicable

4.3.3 Sculpture

Not Yet Used

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Not Yet Used

Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

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.

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.

5.2 Composition

5.2.1 Mineral Content

Not Available

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

5.2.2 Compound Content

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

CaO, Carbon Dioxide, MgO, Silicon 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

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

5.3.3 Weathering

✔ ✘

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

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

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.5

6.5

6.1.2 Grain Size

Not Applicable

Medium to Fine Coarse Grained

6.1.3 Fracture

Conchoidal

Uneven

6.1.4 Streak

White

Bluish Black

6.1.5 Porosity

Very Less Porous

6.1.6 Luster

Vitreous

Subvitreous to Dull

6.1.7 Compressive Strength

What Is Flint

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▼

0.15 N/mm²

Rank: 33 (Overall)▶

90.00 N/mm²

Rank: 22 (Overall)▶

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What Is Obsidian

⊕

▶

175 (What Is Grani..)

◀ ▶ ADD ⊕

6.1.8 Cleavage

Non-Existent

Crenulation and Pervasive

6.1.9 Toughness

Not Available

2.4

6.1.10 Specific Gravity

2.6-2.7

2.86

6.1.11 Transparency

Translucent

Opaque

6.1.12 Density

2.6 g/cm³

2.8-2.9 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

Afghanistan, Indonesia, Japan, Russia

Not Yet Found

7.1.2 Africa

Kenya

Namibia, Uganda

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Germany, Hungary, Italy, Portugal, Spain

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

USA

7.2.2 South America

Argentina, Chile, Ecuador, Peru

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand

New Zealand, Western Australia

All about Obsidian and Tephrite Properties

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