Hornfels

Soapstone

Hornfels and Soapstone

Hornfels

Soapstone

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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

It is a metamorphic magnesium rich rock because it is composed of the mineral talc

History

Origin

New Zealand

USA

Discoverer

Unknown

Etymology

From German which means hornstone

From 17th century, because of its greasy feel and use like a soap

Class

Metamorphic Rocks

Sub-Class

Durable Rock, Soft Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Granular, Platy

Polished

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Black, Black to Grey, Green, Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Dull, Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Bathrooms, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Taken as a Supplement for Calcium or Magnesium

Antiquity Uses

Artifacts, Monuments

Artifacts, Jewellery, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)

Types

Biotite hornfels

Metamorphic rock

Features

Smooth to touch

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.

Composition

Mineral Content

Andalusite

Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz

Compound Content

Fe, Mg

CaO, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

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

Properties

Physical Properties

Hardness

2-31

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal

Streak

Black

Porosity

Highly Porous

Less Porous

Luster

Shiny

Greasy

Compressive Strength

5.80 N/mm²225.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

3.4-3.92.86

0 8.4

👆🏻

Transparency

Opaque

Density

0.25-0.30 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand

Africa

Cameroon, East Africa, Tanzania, Western Africa

Egypt, Ethiopia, Ghana, South Africa, Western Africa

Europe

United Kingdom

Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom

Others

Deposits in Western Continents

North America

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador

Colombia

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

Central Australia, New Zealand, Queensland

All about Hornfels and Soapstone Properties

Know all about Hornfels and Soapstone properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels and Soapstone belong to Metamorphic Rocks.Texture of Hornfels is Granular, Platy whereas that of Soapstone is Polished. Hornfels appears Dull and Soapstone appears Dull, Banded and Foilated. The luster of Hornfels is shiny while that of Soapstone is greasy. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Soapstone is available in black, black to grey, green, grey colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Soapstone are cemetery markers, creating artwork, gemstone, jewelry, manufacture of soap, solvents, dyes, plastics and fibres, production of lime, source of magnesia (mgo).