Tephrite

Skarn

Tephrite and Skarn

Tephrite

Skarn

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Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

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

History

Origin

Germany

USA, Australia

Discoverer

Van Tooren

Tornebohm

Etymology

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

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

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

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

Fine Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Earthy, Mud-rich, Rough

Color

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Landscaping

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

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Production of Lime, Soil Conditioner

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

Types

Igneous rock

Endoskarns

Features

Host Rock for Lead

Host Rock for Lead, Zinc and Copper Deposits

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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.

Composition

Mineral Content

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

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

Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal 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

Medium to Fine Coarse Grained

Fine Grained

Fracture

Uneven

Irregular

Streak

Bluish Black

Light to dark brown

Porosity

Very Less Porous

Less Porous

Luster

Subvitreous to Dull

Waxy and Dull

Compressive Strength

90.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Slaty

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, Impact Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Africa

Namibia, Uganda

South Africa, Western Africa

Europe

Germany, Hungary, Italy, Portugal, Spain

United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada

South America

Brazil, Colombia, Paraguay

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

Central Australia, Western Australia

All about Tephrite and Skarn Properties

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