Slate

Hornfels

Slate and Hornfels

Slate

Hornfels

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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

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock

History

Origin

England

New Zealand

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

From German which means hornstone

Class

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Foliated

Granular, Platy

Color

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

Brown, Dark Greenish - Grey, Green, Reddish Brown

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, 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

Industry

Construction Industry

As Dimension Stone

for Road Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments

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

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

Phyllite, Schist, and Slate

Biotite hornfels

Features

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

Smooth to touch

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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

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

Andalusite

Compound Content

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

Fe, Mg

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

3-42-3

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Splintery

Conchoidal

Streak

Light to dark brown

Porosity

Less Porous

Highly Porous

Luster

Dull

Shiny

Compressive Strength

30.00 N/mm²5.80 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Perfect

Toughness

1.2

Specific Gravity

2.65-2.83.4-3.9

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³0.25-0.30 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.84 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

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand

Africa

Cameroon, East Africa, Tanzania, Western Africa

Europe

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

United Kingdom

Others

Arctic

Deposits in Western Continents

North America

USA

Canada, USA

South America

Brazil

Bolivia, Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

All about Slate and Hornfels Properties

Know all about Slate and Hornfels properties here. All properties of rocks are important as they define the type of rock and its application. Slate and Hornfels belong to Metamorphic Rocks.Texture of Slate is Foliated whereas that of Hornfels is Granular, Platy. Slate appears Dull and Hornfels appears Dull. The luster of Slate is dull while that of Hornfels is shiny. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Hornfels is available in brown, dark greenish - grey, green, reddish brown 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 Hornfels are cemetery markers, commemorative tablets, creating artwork.