Hornfels

Nephelinite

Hornfels and Nephelinite

Hornfels

Nephelinite

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1 Definition

1.1 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

Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).

1.2 History

1.2.1 Origin

New Zealand

Brazil

1.2.2 Discoverer

Unknown

1.3 Etymology

From German which means hornstone

from French néphéline, from Greek nephelē

1.4 Class

Metamorphic Rocks

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Not Applicable

Plutonic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Granular, Platy

Aphanitic

2.2 Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Black, Brown, Colourless, Green, Grey, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Dull

Skeletal

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Homes, Interior Decoration

3.1.2 Exterior Uses

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

for Road Aggregate, Roadstone

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

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

3.4 Other Uses

3.4.1 Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)

4 Types

4.1 Types

Biotite hornfels

Peralkaline Nephelinite

4.2 Features

Smooth to touch

Host Rock for Lead

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

4.3.3 Sculpture

Not Yet Used

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Not Yet Used

Used

4.4 Fossils

Absent

5 Formation

5.1 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.

Nephelinite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

5.2 Composition

5.2.1 Mineral Content

Andalusite

Clinopyroxene, Nepheline, Plagioclase

5.2.2 Compound Content

Fe, Mg

Ca, CaO, Carbon, Cl, MgO

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Not Applicable

Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

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

Chemical Erosion, Water Erosion, Wind Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-36.5

1 7

6.1.2 Grain Size

Fine Grained

6.1.3 Fracture

Conchoidal

Flat

6.1.4 Streak

Unknown

White

6.1.5 Porosity

Highly Porous

Less Porous

6.1.6 Luster

Shiny

Vitreous to Metallic

6.1.7 Compressive Strength

5.80 N/mm²35.00 N/mm²

0.15 450

6.1.8 Cleavage

Perfect

Imperfect

6.1.9 Toughness

Not Yet Found

2.7

6.1.10 Specific Gravity

3.4-3.92.4-2.9

0 8.4

6.1.11 Transparency

Opaque

6.1.12 Density

0.25-0.30 g/cm³2.5-3 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.84 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

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

Japan

7.1.2 Africa

Cameroon, East Africa, Tanzania, Western Africa

Rwanda, Tanzania

7.1.3 Europe

United Kingdom

Not Yet Found

7.1.4 Others

Not Yet Found

Hawaii Islands

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

7.2.2 South America

Bolivia, Brazil, Colombia, Ecuador

Colombia

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, New Zealand, Queensland, Western Australia

Not Yet Found

All about Hornfels and Nephelinite Properties

Know all about Hornfels and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Nephelinite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Nephelinite is Aphanitic. Hornfels appears Dull and Nephelinite appears Skeletal. The luster of Hornfels is shiny while that of Nephelinite is vitreous to metallic. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Nephelinite is available in black, brown, colourless, green, grey, white colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).