Hornfels

Anorthosite

Hornfels and Anorthosite

Hornfels

Anorthosite

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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

Anorthosite is a granular igneous rock composed largely of labradorite or plagioclase

History

Origin

New Zealand

Discoverer

Unknown

Etymology

From German which means hornstone

From French anorthose plagioclase + -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

Foliated, Glassy

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Black, Bluish - Grey, Brown, Green, Grey, Light Greenish Grey, Pink, White

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

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

As Dimension Stone, Cement Manufacture, for Road Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Creating Artwork, Curling

Types

Biotite hornfels

Proterozoic Anorthosite and Archean Anorthosite

Features

Smooth to touch

Generally rough to touch, 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.

Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal mafic component.

Composition

Mineral Content

Andalusite

Amphibole, Clinopyroxene, Ilmenite, Magnetite, Olivine, Orthopyroxene

Compound Content

Fe, Mg

Ca, CaO, Chromium(III) Oxide, MgO, Sulfur Trioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

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

Chemical Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-35-6

1 7

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Grain Size

Fine Grained

Coarse Grained

Fracture

Conchoidal

Irregular

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Shiny

Pearly to Subvitreous

Compressive Strength

5.80 N/mm²180.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

3.4-3.92.62-2.82

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

0.25-0.30 g/cm³2.7-4 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

Heat Resistant, Impact Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Africa

Cameroon, East Africa, Tanzania, Western Africa

Europe

United Kingdom

Bulgaria, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Malta, Poland, Portugal, Romania, Slovenia, Spain, Sweden, The Czech Republic

Others

Deposits in Western Continents

North America

Canada, USA

Canada

South America

Bolivia, Brazil, Colombia, Ecuador

Bolivia, Colombia

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

Central Australia, South Australia, Western Australia

All about Hornfels and Anorthosite Properties

Know all about Hornfels and Anorthosite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Anorthosite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Anorthosite is Foliated, Glassy. Hornfels appears Dull and Anorthosite appears Layered, Banded, Veined and Shiny. The luster of Hornfels is shiny while that of Anorthosite is pearly to subvitreous. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Anorthosite is available in black, bluish - grey, brown, green, grey, light greenish grey, pink, white colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Anorthosite are creating artwork, curling.