Obsidian

Comendite

Obsidian and Comendite

Obsidian

Comendite

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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

Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite

1.2 History

1.2.1 Origin

Ethiopia

Italy

1.2.2 Discoverer

Obsius

Unknown

1.3 Etymology

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

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy

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

Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Porphyritic

2.2 Color

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

Blue, Bluish - 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

Foliated

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, 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

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Cemetery Markers

4 Types

4.1 Types

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

Rhyolite

4.2 Features

Blocks negativity, Helps to protect against depression

Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock

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

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.

Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form 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

Albite, Amphibole, Quartz

5.2.2 Compound Content

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

Al, Fe, Potassium Oxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Cataclastic 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

Coastal Erosion, Water Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.56-7

1 7

6.1.2 Grain Size

Not Applicable

Medium Grained

6.1.3 Fracture

Conchoidal

Pervasive

6.1.4 Streak

White

Bluish Black

6.1.5 Porosity

Very Less Porous

Highly Porous

6.1.6 Luster

Vitreous

Dull

6.1.7 Compressive Strength

0.15 N/mm²92.40 N/mm²

0.15 450

6.1.8 Cleavage

Non-Existent

Not Available

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.6-2.72.38

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

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

China

7.1.2 Africa

Kenya

East Africa

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Italy

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

Queensland

All about Obsidian and Comendite Properties

Know all about Obsidian and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Comendite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Comendite is Porphyritic. Obsidian appears Shiny and Comendite appears Foliated. The luster of Obsidian is vitreous while that of Comendite is dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Comendite is available in blue, bluish - grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Comendite are cemetery markers.