Tephrite

Schist

Tephrite and Schist

Tephrite

Schist

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Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation

History

Origin

Germany

Discoverer

Van Tooren

Unknown

Etymology

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

From French schiste, Greek skhistos i.e. split

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

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

Texture

Aphanitic to Porphyritic

Foliated, Platy

Color

Black, Brown, Green, Grey, White

Black, Blue, Brown, Dark Brown, Green, Grey, Silver

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Layered and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Floor Tiles, Interior Decoration

Exterior Uses

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

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Landscaping

As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts

Other Uses

Commercial Uses

Production of Lime, Soil Conditioner

Used in aquariums, Writing Slates

Types

Igneous rock

Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.

Features

Host Rock for Lead

Easily splits into thin plates, Smooth to touch

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.

Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.

Composition

Mineral Content

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc

Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

CaO, Carbon Dioxide, MgO

Transformation

Metamorphism

✔ ✘

Types of 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

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6.53.5-4

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fracture

Uneven

Conchoidal

Streak

Bluish Black

White

Porosity

Very Less Porous

Highly Porous

Luster

Subvitreous to Dull

Shiny

Compressive Strength

90.00 N/mm²150.00 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Slaty

Toughness

2.4

1.5

Specific Gravity

2.862.5-2.9

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 K0.70 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Impact Resistant, Pressure Resistant, Water Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam

Africa

Namibia, Uganda

Egypt, Ethiopia, Morocco, Nigeria, South Africa

Europe

Germany, Hungary, Italy, Portugal, Spain

Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland

Others

Deposits in Western Continents

North America

USA

Canada, Costa Rica, Cuba, Mexico, Panama, USA

South America

Brazil, Colombia, Guyana

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

New South Wales, New Zealand, Queensland

All about Tephrite and Schist Properties

Know all about Tephrite and Schist properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Schist belongs to Metamorphic Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Schist is Foliated, Platy. Tephrite appears Vesicular and Schist appears Layered and Shiny. The luster of Tephrite is subvitreous to dull while that of Schist is shiny. Tephrite is available in black, brown, green, grey, white colors whereas Schist is available in black, blue, brown, dark brown, green, grey, silver colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Schist are used in aquariums, writing slates.