Obsidian

Felsite

Obsidian and Felsite

Obsidian

Felsite

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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

Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition

History

Origin

Ethiopia

Discoverer

Obsius

Unknown

Etymology

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

From English feldspar and -ite

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy

Arborescent Patterned, Vitreous

Color

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Interior Decoration

Exterior Uses

Garden Decoration

Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Mirror, Jewelry

Types

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

Igneous rock

Features

Blocks negativity, Helps to protect against depression

Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, Very fine grained rock

Archaeological Significance

Monuments

Famous Monuments

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.

Felsite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

Feldspar, Iron Oxides

Compound Content

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Contact 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

Chemical Erosion, Glacier Erosion, Water Erosion

Properties

Physical Properties

Hardness

5-5.55-5.5

1 7

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Grain Size

Fine Grained

Fracture

Conchoidal

Streak

White

Porosity

Very Less Porous

Luster

Vitreous

Compressive Strength

0.15 N/mm²0.15 N/mm²

0.15 450

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Cleavage

Toughness

Specific Gravity

2.6-2.72.6-2.7

0 8.4

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Transparency

Translucent

Density

2.6 g/cm³2.6 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya

Europe

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand

All about Obsidian and Felsite Properties

Know all about Obsidian and Felsite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Felsite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Felsite is Arborescent Patterned, Vitreous. Obsidian appears Shiny and Felsite appears Layered, Banded, Veined and Shiny. The luster of Obsidian and Felsite is vitreous. Obsidian and Felsite are available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Felsite are mirror, jewelry.