Argillite

Obsidian

Argillite and Obsidian

Argillite

Obsidian

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Definition

Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate

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 Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite

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

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Clastic, Polished

Glassy

Color

Dark Grey to Black, Pink, Red, White

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Rough and Dull

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, Garden Decoration, Office Buildings

Garden Decoration

Other Architectural Uses

Curbing, Whetstones

Industry

Construction Industry

Used for flooring, stair treads, borders and window sills.

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery

Other Uses

Commercial Uses

Fire resistant, Used to manufracture paperweights and bookends

Creating Artwork, Mirror, Used in aquariums

Types

Metamorphic rock

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

Features

Is one of the oldest rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.

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

Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz

Compound Content

Iron(III) Oxide, Potassium Oxide, 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, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

2-35-5.5

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal to Uneven

Conchoidal

Streak

White to Grey

White

Porosity

Highly Porous

Very Less Porous

Luster

Waxy and Dull

Vitreous

Compressive Strength

-0.15 N/mm²

0.15 450

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Cleavage

Slaty

Toughness

2.6

Specific Gravity

2.56-2.682.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.54-2.66 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

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

Afghanistan, Indonesia, Japan, Russia

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Kenya

Europe

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

New Zealand

All about Argillite and Obsidian Properties

Know all about Argillite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Argillite belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Argillite is Clastic, Polished whereas that of Obsidian is Glassy. Argillite appears Rough and Dull and Obsidian appears Shiny. The luster of Argillite is waxy and dull while that of Obsidian is vitreous. Argillite is available in dark grey to black, pink, red, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Argillite are fire resistant, used to manufracture paperweights and bookends and that of Obsidian are creating artwork, mirror, used in aquariums.