Obsidian

Pegmatite

Obsidian and Pegmatite

Obsidian

Pegmatite

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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

Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals

1.2 History

1.2.1 Origin

Ethiopia

Unknown

1.2.2 Discoverer

Obsius

R. J. Hauy

1.3 Etymology

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

From Greek pegma, pegmat which means- thing joined together + -ite

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

Plutonic

1.6 Other Categories

Opaque Rock

Coarse Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Pegmatitic

2.2 Color

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

Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow

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

Shiny

Layered, Banded, Veined and Shiny

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone, Paving Stone

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, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Artifacts, Sculpture, Small Figurines

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz

4 Types

4.1 Types

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

Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite

4.2 Features

Blocks negativity, Helps to protect against depression

Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz

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.

Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.

5.2 Composition

5.2.1 Mineral Content

Not Available

Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz

5.2.2 Compound Content

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

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

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

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

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

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.57

1 7

6.1.2 Grain Size

Not Applicable

Medium to Coarse Grained

6.1.3 Fracture

Conchoidal

6.1.4 Streak

White

6.1.5 Porosity

Very Less Porous

Less Porous

6.1.6 Luster

Vitreous

Grainy, Pearly and Vitreous

6.1.7 Compressive Strength

0.15 N/mm²178.54 N/mm²

0.15 450

6.1.8 Cleavage

Non-Existent

Perfect

6.1.9 Toughness

Not Available

2.1

6.1.10 Specific Gravity

2.6-2.72.6-2.63

0 8.4

6.1.11 Transparency

Translucent

Translucent to Opaque

6.1.12 Density

2.6 g/cm³2.6-2.65 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg KNA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea

7.1.2 Africa

Kenya

South Africa

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Canada

7.2.2 South America

Argentina, Chile, Ecuador, Peru

Brazil

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand

New South Wales, Queensland, South Australia, Western Australia

All about Obsidian and Pegmatite Properties

Know all about Obsidian and Pegmatite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Pegmatite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Pegmatite is Pegmatitic. Obsidian appears Shiny and Pegmatite appears Layered, Banded, Veined and Shiny. The luster of Obsidian is vitreous while that of Pegmatite is grainy, pearly and vitreous. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Pegmatite is available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Pegmatite are creating artwork, jewelry, source of corundum, tourmalines, beryls and topaz.