Blueschist

Obsidian

Blueschist and Obsidian

Blueschist

Obsidian

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Definition

Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature

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

USA

Ethiopia

Discoverer

Edgar Bailey

Obsius

Etymology

From French schiste, Greek skhistos i.e. split

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Opaque Rock

Texture

Foliated

Glassy

Color

Blue, Bluish - Grey, Purple, Shades of Blue

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Banded

Shiny

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

Garden Decoration

Other Architectural Uses

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones

Creating Artwork, Mirror, Used in aquariums

Types

Metamorphic rock

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

Features

Has High structural resistance against erosion and climate, Very fine grained rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.

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, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz

Compound Content

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

Mechanical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

3.5-45-5.5

1 7

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Grain Size

Fine to Medium Grained

Fracture

Conchoidal

Streak

White to Grey

White

Porosity

Highly Porous

Very Less Porous

Luster

Dull

Vitreous

Compressive Strength

220.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.5

Specific Gravity

3-3.22.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.8-2.9 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

Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan, Turkey

Afghanistan, Indonesia, Japan, Russia

Africa

Egypt, Ethiopia, South Africa

Kenya

Europe

France, Greece, Iceland

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand

All about Blueschist and Obsidian Properties

Know all about Blueschist and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Blueschist belongs to Metamorphic Rocks while Obsidian belongs to Igneous Rocks.Texture of Blueschist is Foliated whereas that of Obsidian is Glassy. Blueschist appears Dull and Banded and Obsidian appears Shiny. The luster of Blueschist is dull while that of Obsidian is vitreous. Blueschist is available in blue, bluish - grey, purple, shades of blue colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Blueschist are cemetery markers, commemorative tablets, creating artwork, curling, tombstones and that of Obsidian are creating artwork, mirror, used in aquariums.