Skarn

Tephrite

Skarn and Tephrite

Skarn

Tephrite

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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

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

History

Origin

USA, Australia

Germany

Discoverer

Tornebohm

Van Tooren

Etymology

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

From Greek tephra, ashes from Indo-European base, to burn

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Earthy, Mud-rich, Rough

Aphanitic to Porphyritic

Color

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings

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

Landscaping

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Sculpture

Other Uses

Commercial Uses

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

Production of Lime, Soil Conditioner

Types

Endoskarns

Igneous rock

Features

Host Rock for Lead, Zinc and Copper Deposits

Host Rock for Lead

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.

Tephrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

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

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Compound Content

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

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.56.5

1 7

👆🏻

Grain Size

Fine Grained

Medium to Fine Coarse Grained

Fracture

Irregular

Uneven

Streak

Light to dark brown

Bluish Black

Porosity

Less Porous

Very Less Porous

Luster

Waxy and Dull

Subvitreous to Dull

Compressive Strength

70.00 N/mm²90.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Crenulation and Pervasive

Toughness

2.4

Specific Gravity

2.862.86

0 8.4

👆🏻

Transparency

Opaque

Density

2.8-2.9 g/cm³2.8-2.9 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

Africa

South Africa, Western Africa

Namibia, Uganda

Europe

United Kingdom

Germany, Hungary, Italy, Portugal, Spain

Others

Deposits in Western Continents

North America

Canada

USA

South America

Brazil, Colombia, Paraguay

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New Zealand, Western Australia

All about Skarn and Tephrite Properties

Know all about Skarn and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Skarn belongs to Metamorphic Rocks while Tephrite belongs to Igneous Rocks.Texture of Skarn is Earthy, Mud-rich, Rough whereas that of Tephrite is Aphanitic to Porphyritic. Skarn appears Dull and Tephrite appears Vesicular. The luster of Skarn is waxy and dull while that of Tephrite is subvitreous to dull. Skarn and Tephrite are available in black, brown, green, grey, white colors. The commercial uses of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo) and that of Tephrite are production of lime, soil conditioner.