Obsidian

Soapstone

Obsidian and Soapstone

Obsidian

Soapstone

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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

It is a metamorphic magnesium rich rock because it is composed of the mineral talc

History

Origin

Ethiopia

USA

Discoverer

Obsius

Unknown

Etymology

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

From 17th century, because of its greasy feel and use like a soap

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy

Polished

Color

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

Black, Black to Grey, Green, Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Dull, Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Bathrooms, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

Garden Decoration

As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Surgery

Taken as a Supplement for Calcium or Magnesium

Antiquity Uses

Artifacts, Jewellery

Artifacts, Jewellery, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)

Types

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

Metamorphic rock

Features

Blocks negativity, Helps to protect against depression

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire

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.

Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.

Composition

Mineral Content

Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz

Compound Content

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

CaO, Mg, MgO

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

5-5.51

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal

Streak

White

Black

Porosity

Very Less Porous

Less Porous

Luster

Vitreous

Greasy

Compressive Strength

0.15 N/mm²225.00 N/mm²

0.15 450

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Cleavage

Perfect

Toughness

Specific Gravity

2.6-2.72.86

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.6 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand

Africa

Kenya

Egypt, Ethiopia, Ghana, South Africa, Western Africa

Europe

Greece, Hungary, Iceland, Italy, Turkey

Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, USA

South America

Argentina, Chile, Ecuador, Peru

Colombia

Deposits in Oceania Continent

Australia

New Zealand

Central Australia, New Zealand, Queensland

All about Obsidian and Soapstone Properties

Know all about Obsidian and Soapstone properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Soapstone belongs to Metamorphic Rocks.Texture of Obsidian is Glassy whereas that of Soapstone is Polished. Obsidian appears Shiny and Soapstone appears Dull, Banded and Foilated. The luster of Obsidian is vitreous while that of Soapstone is greasy. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Soapstone is available in black, black to grey, green, grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Soapstone are cemetery markers, creating artwork, gemstone, jewelry, manufacture of soap, solvents, dyes, plastics and fibres, production of lime, source of magnesia (mgo).