Pumice

Obsidian

Pumice and Obsidian

Pumice

Obsidian

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Definition

Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals

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

History

Origin

Spain

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From Old French pomis, from a Latin dialect variant of pumex

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Vesicular

Glassy

Color

Beige, Grey, Light Green, Light Grey, Pink, White, Yellow- grey

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

Garden Decoration

Other Architectural Uses

Curbing, Powder

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics

Surgery

Antiquity Uses

Artifacts

Artifacts, Jewellery

Other Uses

Commercial Uses

As a traction material on snow-covered roads, As an abrasive in pencil erasers, Fine abrasive used for polishing, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Used in aquariums

Creating Artwork, Mirror, Used in aquariums

Types

Scoria

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

Features

Host Rock for Lead

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.

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.

Composition

Mineral Content

Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica

Compound Content

Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide

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, Impact 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, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

65-5.5

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Planar

Conchoidal

Streak

White, Greenish White or Grey

White

Porosity

Highly Porous

Very Less Porous

Luster

Earthy

Vitreous

Compressive Strength

51.20 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.862.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

0.25-0.3 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.87 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Africa

Ethiopia, Kenya, Tanzania

Kenya

Europe

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA

Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

New Zealand

All about Pumice and Obsidian Properties

Know all about Pumice and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Pumice and Obsidian belong to Igneous Rocks.Texture of Pumice is Vesicular whereas that of Obsidian is Glassy. Pumice appears Vesicular and Obsidian appears Shiny. The luster of Pumice is earthy while that of Obsidian is vitreous. Pumice is available in beige, grey, light green, light grey, pink, white, yellow- grey colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Pumice are as a traction material on snow-covered roads, as an abrasive in pencil erasers, fine abrasive used for polishing, manufacture of soap, solvents, dyes, plastics and fibres, used in aquariums and that of Obsidian are creating artwork, mirror, used in aquariums.