Shale

Tephrite

Shale and Tephrite

Shale

Tephrite

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Definition

Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

History

Origin

Germany

Discoverer

Johann Gottlob Lehmann

Van Tooren

Etymology

From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,

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

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

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

Clastic, Splintery

Aphanitic to Porphyritic

Color

Black, Brown, Buff, Green, Grey, Red, Yellow

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

Landscaping

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Pottery

Production of Lime, Soil Conditioner

Types

Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale

Igneous rock

Features

Easily splits into thin plates, Generally rough to touch, Very fine grained rock

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Jantar Mantar in India

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.

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

Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

CaO, Carbon Dioxide, MgO, Silicon Dioxide

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

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

Properties

Physical Properties

Hardness

36.5

1 7

👆🏻

Grain Size

Very fine-grained

Medium to Fine Coarse Grained

Fracture

Uneven

Streak

White

Bluish Black

Porosity

Highly Porous

Very Less Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

95.00 N/mm²90.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Crenulation and Pervasive

Toughness

2.6

2.4

Specific Gravity

2.2-2.82.86

0 8.4

👆🏻

Transparency

Opaque

Density

2.4-2.8 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.39 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Namibia, Uganda

Europe

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Germany, Hungary, Italy, Portugal, Spain

Others

Deposits in Western Continents

North America

USA

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

New Zealand, Western Australia

All about Shale and Tephrite Properties

Know all about Shale and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Tephrite belongs to Igneous Rocks.Texture of Shale is Clastic, Splintery whereas that of Tephrite is Aphanitic to Porphyritic. Shale appears Muddy and Tephrite appears Vesicular. The luster of Shale is dull while that of Tephrite is subvitreous to dull. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Tephrite is available in black, brown, green, grey, white colors. The commercial uses of Shale are creating artwork, pottery and that of Tephrite are production of lime, soil conditioner.