Hornfels

Dunite

Hornfels and Dunite

Hornfels

Dunite

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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

Dunite is a green to brownish coarse-grained igneous rock mainly consisting of olivine

History

Origin

New Zealand

Discoverer

Unknown

Ferdinand von Hochstetter

Etymology

From German which means hornstone

From the name of Dun Mountain, New Zealand, + -ite1

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Granular, Platy

Phaneritic

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Dark Greenish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds

Types

Biotite hornfels

Dunite

Features

Smooth to touch

Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

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.

Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. It can be formed in two ways.

Composition

Mineral Content

Andalusite

Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene

Compound Content

Fe, Mg

Ca, CaO, Fe, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

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

Coastal Erosion, Glacier Erosion, Water Erosion

Properties

Physical Properties

Hardness

2-33.5-4

1 7

👆🏻

Grain Size

Fine Grained

Coarse Grained

Fracture

Conchoidal

Irregular

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Shiny

Compressive Strength

5.80 N/mm²107.55 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

3.4-3.93-3.01

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

0.25-0.30 g/cm³2.84-2.85 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K1.25 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey

Africa

Cameroon, East Africa, Tanzania, Western Africa

Morocco, South Africa

Europe

United Kingdom

Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador

Argentina, Brazil, Colombia, Ecuador, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

New Zealand, Western Australia

All about Hornfels and Dunite Properties

Know all about Hornfels and Dunite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Dunite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Dunite is Phaneritic. Hornfels appears Dull and Dunite appears Rough and Shiny. The luster of Hornfels and Dunite is shiny. Hornfels and Dunite are available in brown, dark greenish - grey, green, reddish brown colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Dunite are creating artwork, gemstone, jewelry, source of chromite, platinum, nickel and garnet, source of diamonds.