Shale

Obsidian

Shale and Obsidian

Shale

Obsidian

Add ⊕

Definition

Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles

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

Johann Gottlob Lehmann

Obsius

Etymology

From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,

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

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Clastic, Splintery

Glassy

Color

Black, Brown, Buff, Green, Grey, Red, Yellow

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Sculpture

Artifacts, Jewellery

Other Uses

Commercial Uses

Creating Artwork, Pottery

Creating Artwork, Mirror, Used in aquariums

Types

Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale

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

Features

Easily splits into thin plates, Generally rough to touch, Very fine grained rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Jantar Mantar in India

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.

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

Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

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

35-5.5

1 7

👆🏻

Grain Size

Very fine-grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Dull

Vitreous

Compressive Strength

95.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.6

Specific Gravity

2.2-2.82.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.4-2.8 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.39 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 Shale and Obsidian Properties

Know all about Shale and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Shale is Clastic, Splintery whereas that of Obsidian is Glassy. Shale appears Muddy and Obsidian appears Shiny. The luster of Shale is dull while that of Obsidian is vitreous. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Shale are creating artwork, pottery and that of Obsidian are creating artwork, mirror, used in aquariums.