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
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
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Granular, Platy
Earthy, Mud-rich, Rough
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Green, Grey, White
Durability
Durable
Durable
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
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
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Biotite hornfels
Endoskarns
Features
Smooth to touch
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
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.
Mineral Content
Andalusite
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Fe, Mg
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering
-
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
-
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Irregular
Streak
-
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Shiny
Waxy and Dull
Specific Gravity
3.4-3.9
2.86
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
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
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
Hornfels vs Skarn Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Hornfels vs Skarn characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Skarn. Learn more about Hornfels vs Skarn in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Skarn include Decorative aggregates, Entryways and Interior decoration. Due to some exceptional properties of Hornfels and Skarn, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Skarn include 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.
More about Hornfels and Skarn
Here you can know more about Hornfels and Skarn. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Skarn consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Skarn includes Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Skarn, the texture, color and appearance plays an important role in determining the type of rock. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas, Skarn is available in black, brown, green, grey, white colors. Appearance of Hornfels is Dull and that of Skarn is Dull. Properties of rock is another aspect for Hornfels vs Skarn. The hardness of Hornfels is 2-3 and that of Skarn is 6.5. The types of Hornfels are Biotite hornfels whereas types of Skarn are Endoskarns. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Hornfels is while that of Skarn is light to dark brown. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Skarn is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Hornfels is heat resistant, impact resistant, pressure resistant whereas Skarn is heat resistant.