Hornfels

Argillite

Hornfels and Argillite

Hornfels

Argillite

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Definition

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

Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate

History

Origin

New Zealand

Discoverer

Unknown

Etymology

From German which means hornstone

From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Granular, Platy

Clastic, Polished

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Dark Grey to Black, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Rough and Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

for Road Aggregate, Roadstone

Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Fire resistant, Used to manufracture paperweights and bookends

Types

Biotite hornfels

Metamorphic rock

Features

Smooth to touch

Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

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.

An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.

Composition

Mineral Content

Andalusite

Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz

Compound Content

Fe, Mg

Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

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

Chemical Erosion

Properties

Physical Properties

Hardness

2-32-3

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal

Conchoidal to Uneven

Streak

White to Grey

Porosity

Highly Porous

Luster

Shiny

Waxy and Dull

Compressive Strength

5.80 N/mm²-

0.15 450

👆🏻

Cleavage

Perfect

Slaty

Toughness

2.6

Specific Gravity

3.4-3.92.56-2.68

0 8.4

👆🏻

Transparency

Opaque

Density

0.25-0.30 g/cm³2.54-2.66 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Bangladesh, China, India, Russia

Africa

Cameroon, East Africa, Tanzania, Western Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Europe

United Kingdom

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

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Bolivia, Brazil, Colombia, Ecuador

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

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

All about Hornfels and Argillite Properties

Know all about Hornfels and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Argillite belongs to Sedimentary Rocks.Texture of Hornfels is Granular, Platy whereas that of Argillite is Clastic, Polished. Hornfels appears Dull and Argillite appears Rough and Dull. The luster of Hornfels is shiny while that of Argillite is waxy and dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Argillite is available in dark grey to black, pink, red, white colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Argillite are fire resistant, used to manufracture paperweights and bookends.