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Hornfels and Gabbro


Gabbro and Hornfels


Definition

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  
Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt  

History
  
  

Origin
New Zealand  
Germany  

Discoverer
Unknown  
Christian Leopold von Buch  

Etymology
From German which means hornstone  
From Latin glaber bare, smooth, bald  

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

Texture
Granular, Platy  
Phaneritic  

Color
Brown, Dark Greenish - Grey, Green, Reddish Brown  
Dark Grey to Black  

Maintenance
Less  
Less  

Durability
Durable  
Durable  

Water Resistant
Yes  
Yes  

Scratch Resistant
No  
Yes  

Stain Resistant
No  
Yes  

Wind Resistant
No  
Yes  

Acid Resistant
No  
Yes  

Appearance
Dull  
Veined and Shiny  

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

Other Architectural Uses
Curbing  
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, Monuments, Sculpture  

Other Uses
  
  

Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork  
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones  

Types

Types
Biotite hornfels  
Anorthosite Gabbro and Norite Gabbro  

Features
Smooth to touch  
Smooth to touch  

Archaeological Significance
  
  

Monuments
-  
-  

Famous Monuments
-  
-  

Sculpture
-  
-  

Famous Sculptures
-  
-  

Pictographs
-  
-  

Petroglyphs
-  
-  

Figurines
-  
-  

Fossils
Absent  
Absent  

Formation

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.  
Gabbro, a mafic rock, forms due to cooling and crystallization of magma underneath Earth's surface.  

Composition
  
  

Mineral Content
Andalusite  
Augite, Olivine, Plagioclase, 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
No  
Yes  

Types of Metamorphism
-  
Impact Metamorphism  

Weathering
Yes  
Yes  

Types of Weathering
Biological Weathering  
Chemical Weathering  

Erosion
Yes  
Yes  

Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion  
Coastal Erosion  

Properties

Physical Properties
  
  

Hardness
2-3  
7  

Grain Size
Fine Grained  
Coarse Grained  

Fracture
Conchoidal  
Conchoidal  

Streak
-  
Black  

Porosity
Highly Porous  
Highly Porous  

Luster
Shiny  
-  

Compressive Strength
5.80 N/mm2  
99+
225.00 N/mm2  
8

Cleavage
Perfect  
-  

Toughness
-  
1.6  

Specific Gravity
3.4-3.9  
2.86-2.87  

Transparency
Opaque  
Opaque  

Density
0.25-0.30 g/cm3  
2.7-3.3 g/cm3  

Thermal Properties
  
  

Specific Heat Capacity
0.84 kJ/Kg K  
15
0.71 kJ/Kg K  
23

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  
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  

Summary >>
<< Reserves

All about Hornfels and Gabbro Properties

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

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