Obsidian

Andesite

Obsidian and Andesite

Obsidian

Andesite

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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

Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava

History

Origin

Ethiopia

North America

Discoverer

Obsius

Theodor von Gümbel

Etymology

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

From Andes mountains, where it is found in abundance

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy

Aphanitic to Porphyritic

Color

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

Bluish - Grey, Grey, Pink, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens

Exterior Uses

Garden Decoration

Office Buildings, Roof Tiles

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Cobblestones, Construction Aggregate, for Road Aggregate

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Commemorative Tablets, Creating Artwork

Types

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

Icelandite

Features

Blocks negativity, Helps to protect against depression

Generally rough to touch, High silica content, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Middle of the Earth in Ecuador

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.

Composition

Mineral Content

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon

Compound Content

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

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

5-5.57

1 7

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Grain Size

Very fine-grained

Fracture

Conchoidal

Uneven

Streak

White

Porosity

Very Less Porous

Less Porous

Luster

Vitreous

Compressive Strength

0.15 N/mm²225.00 N/mm²

0.15 450

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Cleavage

Toughness

1.1

Specific Gravity

2.6-2.72.5-2.8

0 8.4

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Transparency

Translucent

Opaque

Density

2.6 g/cm³2.11-2.36 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K2.39 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

India, Indonesia, Japan, Nepal, South Korea

Africa

Kenya

Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania

Europe

Greece, Hungary, Iceland, Italy, Turkey

Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New Zealand

New South Wales, New Zealand, Western Australia

All about Obsidian and Andesite Properties

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