Obsidian

Metapelite

Obsidian and Metapelite

Obsidian

Metapelite

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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

Metapelite is an old and currently not widely used field geological term for a clay rich fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone

History

Origin

Ethiopia

Discoverer

Obsius

Unknown

Etymology

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

From Pelos or clay in Greek

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Glassy

Foliated

Color

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

Dark Greenish - Grey, Green, Light Green, Light Greenish Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Cement Manufacture, Construction Aggregate, for Road Aggregate

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts

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

Metamorphic rock

Features

Blocks negativity, Helps to protect against depression

Easily splits into thin plates, It is One of the Oldest, Strongest and Hardest 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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Metapelite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

Albite, Chlorite, Quartz

Compound Content

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

Aluminium Oxide, CaO, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

5-5.55-6

1 7

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Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Fibrous

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Vitreous

Earthy

Compressive Strength

0.15 N/mm²40.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.6-2.73.4-3.7

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.6 g/cm³0-300 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.72 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya

Western Africa

Europe

Greece, Hungary, Iceland, Italy, Turkey

United Kingdom

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New Zealand

Central Australia, Western Australia

All about Obsidian and Metapelite Properties

Know all about Obsidian and Metapelite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Metapelite belongs to Metamorphic Rocks.Texture of Obsidian is Glassy whereas that of Metapelite is Foliated. Obsidian appears Shiny and Metapelite appears Banded. The luster of Obsidian is vitreous while that of Metapelite is earthy. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Metapelite is available in dark greenish - grey, green, light green, light greenish grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Metapelite are commemorative tablets, creating artwork.