Scoria

Obsidian

Scoria and Obsidian

Scoria

Obsidian

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Definition

Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities

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

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung

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

Black, Brown, Dark Grey to Black, Red

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy and Vesicular

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Cement Manufacture, Construction Aggregate, for Road Aggregate, In landscaping and drainage works

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery

Other Uses

Commercial Uses

As a traction material on snow-covered roads, Creating Artwork, High-temperature insulation, In gas barbecue grills

Creating Artwork, Mirror, Used in aquariums

Types

Basaltic Scoria and Andesitic Scoria

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

Features

Available in Lots of Colors and Patterns, Generally rough to touch, Surfaces are often shiny

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Scoria forms when magma containing huge amount of dissolved gas flows from a volcano during an eruption.

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

Apatite, Biotite, Calcite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz, Silica

Compound Content

Ca, NaCl

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

5-65-5.5

1 7

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Grain Size

Fine Grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Subvitreous to Dull

Vitreous

Compressive Strength

70.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

-99992.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

-9999 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear 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 Scoria and Obsidian Properties

Know all about Scoria and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Scoria and Obsidian belong to Igneous Rocks.Texture of Scoria is Vesicular whereas that of Obsidian is Glassy. Scoria appears Glassy and Vesicular and Obsidian appears Shiny. The luster of Scoria is subvitreous to dull while that of Obsidian is vitreous. Scoria is available in black, brown, dark grey to black, red colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Scoria are as a traction material on snow-covered roads, creating artwork, high-temperature insulation, in gas barbecue grills and that of Obsidian are creating artwork, mirror, used in aquariums.