Slate

Tephrite

Slate and Tephrite

Slate

Tephrite

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Definition

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

History

Origin

England

Germany

Discoverer

Abraham Gottlob Werner

Van Tooren

Etymology

From Old French esclate, from esclat (French éclat)

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

Class

Metamorphic 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

Foliated

Aphanitic to Porphyritic

Color

Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue

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

Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads

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 Dimension Stone

Landscaping

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Sculpture

Other Uses

Commercial Uses

Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates

Production of Lime, Soil Conditioner

Types

Phyllite, Schist, and Slate

Igneous rock

Features

Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.

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

Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic 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

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

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

Properties

Physical Properties

Hardness

3-46.5

1 7

👆🏻

Grain Size

Very fine-grained

Medium to Fine Coarse Grained

Fracture

Splintery

Uneven

Streak

Light to dark brown

Bluish Black

Porosity

Less Porous

Very Less Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

30.00 N/mm²90.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Crenulation and Pervasive

Toughness

1.2

2.4

Specific Gravity

2.65-2.82.86

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

Africa

Namibia, Uganda

Europe

Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom

Germany, Hungary, Italy, Portugal, Spain

Others

Arctic

Deposits in Western Continents

North America

USA

South America

Brazil

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

All about Slate and Tephrite Properties

Know all about Slate and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Tephrite belongs to Igneous Rocks.Texture of Slate is Foliated whereas that of Tephrite is Aphanitic to Porphyritic. Slate appears Dull and Tephrite appears Vesicular. The luster of Slate is dull while that of Tephrite is subvitreous to dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Tephrite is available in black, brown, green, grey, white colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates and that of Tephrite are production of lime, soil conditioner.