Hornfels

Kimberlite

Hornfels and Kimberlite

Hornfels

Kimberlite

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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

Kimberlite is a rare, blue-tinged, coarse-grained intrusive igneous rock, which sometimes contains diamonds and is mostly found in South Africa and Siberia.

History

Origin

New Zealand

Kimberley, South Africa

Discoverer

Unknown

John W. Judd

Etymology

From German which means hornstone

From Kimberley +‎ -ite, from the name of the South African town of Kimberley where the rock was first found.

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Opaque Rock

Texture

Granular, Platy

Porphyritic

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Black, Bluish - Grey, Brown, Dark Greenish - Grey, Green, Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Dull and Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Countertops, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement, Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Taken as a Supplement for Calcium or Magnesium

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO)

Types

Biotite hornfels

Basaltic Kimberlites and Micaceous Kimberlites

Features

Smooth to touch

Always found as volcanic pipes over deep continental crust, Host rock for Diamond, Is one of the oldest rock, Surfaces are often shiny

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.

Kimberlite is an igneous rock and is the main source of diamonds. Its formation takes place deep beneath the Earth’s surface between 150 to 450 kilometres, and are erupted rapidly and violently.

Composition

Mineral Content

Andalusite

Garnet, Olivine, Phlogopite, Pyroxene

Compound Content

Fe, Mg

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal 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

Fine to Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Shiny

Subvitreous to Dull

Compressive Strength

5.80 N/mm²260.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Conchoidal

Toughness

Specific Gravity

3.4-3.92.86-2.87

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

0.25-0.30 g/cm³2.95-2.96 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, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Russia

Africa

Cameroon, East Africa, Tanzania, Western Africa

Angola, Botswana, Cameroon, Ethiopia, South Africa

Europe

United Kingdom

England, Hungary, Iceland, United Kingdom

Others

Antarctica

Deposits in Western Continents

North America

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador

Argentina, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

New South Wales, New Zealand, South Australia, Western Australia

All about Hornfels and Kimberlite Properties

Know all about Hornfels and Kimberlite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Kimberlite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Kimberlite is Porphyritic. Hornfels appears Dull and Kimberlite appears Dull and Banded. The luster of Hornfels is shiny while that of Kimberlite is subvitreous to dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Kimberlite is available in black, bluish - grey, brown, dark greenish - grey, green, grey colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Kimberlite are an oil and gas reservoir, as a feed additive for livestock, gemstone, metallurgical flux, production of lime, soil conditioner, source of magnesia (mgo).