Obsidian

Lherzolite

Obsidian and Lherzolite

Obsidian

Lherzolite

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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

Lherzolite is a type of ultramafic igneous rock which contains essential olivine and clinopyroxene and orthopyroxene in equal proportions

History

Origin

Ethiopia

France

Discoverer

Obsius

Unknown

Etymology

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

From the Lherz Massif, an alpine peridotite complex, at Étang de Lers, near Massat in the French Pyrenees; Lherz is the archaic spelling of this location

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Plutonic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy

Grenue

Color

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

Black, Dark Greenish - Grey, Green, Pink, Purple

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Glassy, Vesicular and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Homes, Interior Decoration

Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Landscaping, Manufacture of Magnesium and Dolomite Refractories, Used for flooring, stair treads, borders and window sills.

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

As armour rock for sea walls, Source of Magnesia (MgO), Used in aquariums

Types

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

Garnet Lherzolite

Features

Blocks negativity, Helps to protect against depression

Host Rock for Lead

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.

Lherzolite 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

Harzburgite, Olivine, Pyroxene, Pyrrhotite

Compound Content

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

CaO, Cr, Chromium(III) Oxide, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact 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, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

5-5.56.5

1 7

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Grain Size

Fine Grained

Fracture

Conchoidal

Streak

White

Porosity

Very Less Porous

Less Porous

Luster

Vitreous

Subvitreous to Dull

Compressive Strength

0.15 N/mm²290.00 N/mm²

0.15 450

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Cleavage

Perfect

Toughness

2.7

Specific Gravity

2.6-2.72.86

0 8.4

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Transparency

Translucent

Opaque

Density

2.6 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.95 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Russia, South Korea

Africa

Kenya

Western Africa

Europe

Greece, Hungary, Iceland, Italy, Turkey

United Kingdom

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

USA

South America

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand

Central Australia, Western Australia

All about Obsidian and Lherzolite Properties

Know all about Obsidian and Lherzolite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Lherzolite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Lherzolite is Grenue. Obsidian appears Shiny and Lherzolite appears Glassy, Vesicular and Foilated. The luster of Obsidian is vitreous while that of Lherzolite is subvitreous to dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Lherzolite is available in black, dark greenish - grey, green, pink, purple colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Lherzolite are as armour rock for sea walls, source of magnesia (mgo), used in aquariums.