Obsidian

Pseudotachylite

Obsidian and Pseudotachylite

Obsidian

Pseudotachylite

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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

Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.

1.2 History

1.2.1 Origin

Ethiopia

USA

1.2.2 Discoverer

Obsius

Unknown

1.3 Etymology

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

From pseudo- +‎ tachylite, a glassy rock generated by frictional heat within faults.

1.4 Class

Igneous Rocks

Metamorphic Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

Not Applicable

1.6 Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Quench

2.2 Color

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

Black, Brown, Colourless, Green, Grey, Pink, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

81% Igneous Rocks Rocks have it !

✔ ✘

81% Metamorphic Rocks Rocks have it !

2.4.2 Scratch Resistant

✔ ✘

86% Igneous Rocks Rocks have it !

✔ ✘

65% Metamorphic Rocks Rocks have it !

2.4.3 Stain Resistant

✔ ✘

66% Igneous Rocks Rocks have it !

✔ ✘

42% Metamorphic Rocks Rocks have it !

2.4.4 Wind Resistant

✔ ✘

49% Igneous Rocks Rocks have it !

✔ ✘

19% Metamorphic Rocks Rocks have it !

2.4.5 Acid Resistant

✔ ✘

48% Igneous Rocks Rocks have it !

✔ ✘

15% Metamorphic Rocks Rocks have it !

2.5 Appearance

Shiny

Dull and Soft

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration

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

As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Artifacts, Monuments

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Creating Artwork, Gemstone

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

Used

4.3.2 Famous Monuments

Not Applicable

Data Not Available

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Not Yet 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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

5.2 Composition

5.2.1 Mineral Content

Not Available

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

5.2.2 Compound Content

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

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

97% Igneous Rocks Rocks have it !

✔ ✘

50% Metamorphic Rocks Rocks have it !

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

✔ ✘

99% Igneous Rocks Rocks have it !

✔ ✘

65% Metamorphic Rocks Rocks have it !

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Not Applicable

5.3.5 Erosion

✔ ✘

92% Igneous Rocks Rocks have it !

✔ ✘

77% Metamorphic Rocks Rocks have it !

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Not Applicable

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.5

6.1.2 Grain Size

Not Applicable

Very fine-grained

6.1.3 Fracture

Conchoidal

Uneven

6.1.4 Streak

White

Light to dark brown

6.1.5 Porosity

Very Less Porous

Less Porous

6.1.6 Luster

Vitreous

6.1.7 Compressive Strength

What Is Flint

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0.15 N/mm²

Rank: 33 (Overall)▶

60.00 N/mm²

Rank: 25 (Overall)▶

▲

What Is Obsidian

⊕

▶

175 (What Is Grani..)

◀ ▶ ADD ⊕

6.1.8 Cleavage

Non-Existent

Irregular

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.6-2.7

2.46-2.86

6.1.11 Transparency

Translucent

Transparent to Translucent

6.1.12 Density

2.6 g/cm³

2.7-2.9 g/cm³

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

What Is Banded ..

⊕

▶

▼

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

Heat Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

South Korea

7.1.2 Africa

Kenya

Western Africa

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Great Britain, Switzerland

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Not Yet Found

7.2.2 South America

Argentina, Chile, Ecuador, Peru

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand

Central Australia, Western Australia

All about Obsidian and Pseudotachylite Properties

Know all about Obsidian and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Obsidian is Glassy whereas that of Pseudotachylite is Quench. Obsidian appears Shiny and Pseudotachylite appears Dull and Soft. The luster of Obsidian and Pseudotachylite is vitreous. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Pseudotachylite are creating artwork, gemstone.