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
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
History
Origin
New Zealand
USA, Australia
Discoverer
Unknown
Tornebohm
Etymology
From German which means hornstone
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Granular, Platy
Earthy, Mud-rich, Rough
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Green, Grey, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull
Dull
Uses
Architecture
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
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, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Medical Industry
Not Available
Not Applicable
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Types
Biotite hornfels
Endoskarns
Features
Smooth to touch
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Not Available
Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Used
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Composition
Mineral Content
Andalusite
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Fe, Mg
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering
Not Applicable
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Not Applicable
Properties
Physical Properties
Hardness
2-36.5
1
7
👆🏻
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Irregular
Streak
Unknown
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Shiny
Waxy and Dull
Compressive Strength
5.80 N/mm2NA
0.15
450
👆🏻
Cleavage
Perfect
Slaty
Toughness
Not Available
2.4
Specific Gravity
3.4-3.92.86
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm32.8-2.9 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
Reserves
Deposits in Eastern Continents
Asia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Cameroon, East Africa, Tanzania, Western Africa
South Africa, Western Africa
Europe
United Kingdom
United Kingdom
Others
Not Available
Not Available
Deposits in Western Continents
North America
Canada, USA
Canada
South America
Bolivia, Brazil, Colombia, Ecuador
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
Central Australia, Western Australia