Slate

Greywacke

Slate and Greywacke

Slate

Greywacke

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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

Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay

History

Origin

England

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

From German Grauwacke, from grau grey + wacke

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Foliated

Clastic

Color

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

Beige, Black, Brown, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Uses

Architecture

Interior Uses

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

Decorative Aggregates, Floor Tiles, 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, Paving Stone

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

As Dimension Stone

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Sculpture, Small Figurines

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

As armour rock for sea walls, Petroleum reservoirs, Sea Defence, Tombstones

Types

Phyllite, Schist, and Slate

Greywacke

Features

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

Available in Lots of Colors and Patterns, Generally rough to touch, Non-vesicular, Veined

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

Graywacke rock is a type of sedimentary rock, which is also known as immature sandstone, which is indurated, dark grey and consisting of poorly sorted angular to sub-angular, sand-sized grains.

Composition

Mineral Content

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

Augite, Biotite, Calcite, Chlorite, Clay, Clay Minerals, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz

Compound Content

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

Aluminium Oxide, NaCl, CaO, Chromium(III) Oxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Coastal Erosion, Sea Erosion, Wind Erosion

Properties

Physical Properties

Hardness

3-46-7

1 7

👆🏻

Grain Size

Very fine-grained

Angular and Fine

Fracture

Splintery

Conchoidal

Streak

Light to dark brown

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Compressive Strength

30.00 N/mm²120.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Perfect

Toughness

1.2

2.6

Specific Gravity

2.65-2.82.2-2.8

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³2.6-2.61 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.71 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

Africa

Namibia, Nigeria, South Africa

Europe

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

Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom

Others

Arctic

Greenland

Deposits in Western Continents

North America

USA

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand

All about Slate and Greywacke Properties

Know all about Slate and Greywacke properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Greywacke belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Greywacke is Clastic. Slate appears Dull and Greywacke appears Dull. The luster of Slate and Greywacke is dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Greywacke is available in beige, black, brown, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow 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 Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones.