Hornfels

Trondhjemite

Hornfels and Trondhjemite

Hornfels

Trondhjemite

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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

Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.

History

Origin

New Zealand

Tonale, Italy

Discoverer

Unknown

Etymology

From German which means hornstone

From Trondheim, Norway

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, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Granular, Platy

Phaneritic

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Black, Brown, Light to Dark Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Cemetery Markers, Creating Artwork

Types

Biotite hornfels

Intermediate intrusive rock

Features

Smooth to touch

Is one of the oldest rock, Typically speckled black and white.

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.

When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.

Composition

Mineral Content

Andalusite

Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon

Compound Content

Fe, Mg

NaCl, CaO, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact 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, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-36-7

1 7

👆🏻

Grain Size

Fine Grained

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

Bluish Black

Porosity

Highly Porous

Very Less Porous

Luster

Shiny

Subvitreous to Dull

Compressive Strength

5.80 N/mm²130.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

3.4-3.92.86-3

0 8.4

👆🏻

Transparency

Opaque

Density

0.25-0.30 g/cm³2.73 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.92 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

Africa

Cameroon, East Africa, Tanzania, Western Africa

Egypt

Europe

United Kingdom

Finland, Germany, Italy, Romania, Sweden, Turkey

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Bolivia, Brazil, Colombia, Ecuador

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

New Zealand, South Australia, Western Australia

All about Hornfels and Trondhjemite Properties

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