Hornfels

Pyroxenite

Hornfels and Pyroxenite

Hornfels

Pyroxenite

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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

Pyroxenite is a dark, greenish, granular intrusive igneous rock consisting mainly of pyroxenes and olivine

History

Origin

New Zealand

Discoverer

Unknown

Etymology

From German which means hornstone

From pyro- fire + Greek xenos stranger as the mineral group was new to igneous rocks

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Granular, Platy

Clastic, Granular, Phaneritic, Porphyritic

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration, Kitchens

Exterior Uses

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

As Building Stone, As Facing Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones

Types

Biotite hornfels

Clinopyroxenites, Orthopyroxenites and Websterites

Features

Smooth to touch

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.

Pyroxenites are ultramafic igneous rocks which are made up of minerals of the pyroxene group, such as augite and diopside, hypersthene, bronzite or enstatite.

Composition

Mineral Content

Andalusite

Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene

Compound Content

Fe, Mg

Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Impact Metamorphism, Regional 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

Chemical Erosion, Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

2-37

1 7

👆🏻

Grain Size

Fine Grained

Coarse Grained

Fracture

Conchoidal

Uneven

Streak

White, Greenish White or Grey

Porosity

Highly Porous

Less Porous

Luster

Shiny

Dull to Vitreous to Submetallic

Compressive Strength

5.80 N/mm²150.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

3.4-3.93.2-3.5

0 8.4

👆🏻

Transparency

Opaque

Density

0.25-0.30 g/cm³3.1-3.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

India, Russia

Africa

Cameroon, East Africa, Tanzania, Western Africa

South Africa

Europe

United Kingdom

Germany, Greece, Italy, Scotland, Turkey

Others

Greenland

Deposits in Western Continents

North America

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador

Brazil, Colombia, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

New Zealand, Queensland

All about Hornfels and Pyroxenite Properties

Know all about Hornfels and Pyroxenite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Pyroxenite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Pyroxenite is Clastic, Granular, Phaneritic, Porphyritic. Hornfels appears Dull and Pyroxenite appears Layered, Banded, Veined and Shiny. The luster of Hornfels is shiny while that of Pyroxenite is dull to vitreous to submetallic. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Pyroxenite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Pyroxenite are cemetery markers, commemorative tablets, laboratory bench tops, jewelry, sea defence, tombstones.