Obsidian

Adakite

Obsidian and Adakite

Obsidian

Adakite

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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

Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs

1.2 History

1.2.1 Origin

Ethiopia

Adak, Aleutian Islands

1.2.2 Discoverer

Obsius

Defant and Drummond

1.3 Etymology

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

From Adak, Aleutian Islands

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Porphyritic

2.2 Color

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

Black, Brown, Light to Dark Grey

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

Dull and Soft

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens

3.1.2 Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone, Office Buildings

3.1.3 Other Architectural Uses

Not Yet Used

Whetstones

3.2 Industry

3.2.1 Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Monuments, Sculpture, Small Figurines

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Commemorative Tablets, Pottery, Used in aquariums

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

Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock

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

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Used

4.3.6 Petroglyphs

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.

Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.

5.2 Composition

5.2.1 Mineral Content

Not Available

Olivine, 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

Aluminium Oxide, MgO, Silicon Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Coastal Erosion, Sea Erosion, Water Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.53-4

1 7

6.1.2 Grain Size

Not Applicable

Fine to Medium Grained

6.1.3 Fracture

Conchoidal

6.1.4 Streak

White

Bluish Black

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/mm²NA

0.15 450

6.1.8 Cleavage

Non-Existent

Not Available

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.6-2.7Not Available

0 8.4

6.1.11 Transparency

Translucent

Opaque

6.1.12 Density

2.6 g/cm³Not Available

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, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

India, Russia

7.1.2 Africa

Kenya

Ethiopia, Somalia, South Africa

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Iceland

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Canada, USA

7.2.2 South America

Argentina, Chile, Ecuador, Peru

Brazil

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand

Not Yet Found

All about Obsidian and Adakite Properties

Know all about Obsidian and Adakite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Adakite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Adakite is Porphyritic. Obsidian appears Shiny and Adakite appears Dull and Soft. The luster of Obsidian is vitreous while that of Adakite is grainy, pearly and vitreous. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Adakite is available in black, brown, light to dark grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Adakite are commemorative tablets, pottery, used in aquariums.