Skarn

Obsidian

Skarn and Obsidian

Skarn

Obsidian

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Definition

Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin

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, Australia

Ethiopia

Discoverer

Tornebohm

Obsius

Etymology

From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Earthy, Mud-rich, Rough

Glassy

Color

Black, Brown, Green, Grey, White

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)

Creating Artwork, Mirror, Used in aquariums

Types

Endoskarns

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

Features

Host Rock for Lead, Zinc and Copper Deposits

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

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

Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite

Compound Content

Au, CaO, Carbon Dioxide, Cu, Fe, MgO

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, Hydrothermal Metamorphism, Impact Metamorphism, Regional 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

6.55-5.5

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Irregular

Conchoidal

Streak

Light to dark brown

White

Porosity

Less Porous

Very Less Porous

Luster

Waxy and Dull

Vitreous

Compressive Strength

70.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.4

Specific Gravity

2.862.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.8-2.9 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Russia, Saudi Arabia, South Korea, Sri Lanka

Afghanistan, Indonesia, Japan, Russia

Africa

South Africa, Western Africa

Kenya

Europe

United Kingdom

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

Canada

Canada, Mexico, USA

South America

Brazil, Colombia, Paraguay

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New Zealand

All about Skarn and Obsidian Properties

Know all about Skarn and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Skarn belongs to Metamorphic Rocks while Obsidian belongs to Igneous Rocks.Texture of Skarn is Earthy, Mud-rich, Rough whereas that of Obsidian is Glassy. Skarn appears Dull and Obsidian appears Shiny. The luster of Skarn is waxy and dull while that of Obsidian is vitreous. Skarn is available in black, brown, green, grey, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo) and that of Obsidian are creating artwork, mirror, used in aquariums.