Hornfels and Scoria
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
Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities
History
Origin
New Zealand
Unknown
Discoverer
Unknown
Unknown
Etymology
From German which means hornstone
From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Granular, Platy
Vesicular
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Dark Grey to Black, Red
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
No
Yes
Stain Resistant
No
No
Wind Resistant
No
No
Acid Resistant
No
No
Appearance
Dull
Glassy and Vesicular
Uses
Architecture
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
for Road Aggregate, Roadstone
Cement Manufacture, Construction Aggregate, for Road Aggregate, In landscaping and drainage works
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
As a traction material on snow-covered roads, Creating Artwork, High-temperature insulation, In gas barbecue grills
Types
Types
Biotite hornfels
Not Available
Features
Smooth to touch
Available in Lots of Colors and Patterns, Generally rough to touch, Surfaces are often shiny
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Used
Used
Petroglyphs
Used
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.
Scoria forms when magma containing huge amount of dissolved gas flows from a volcano during an eruption.
Composition
Mineral Content
Andalusite
Apatite, Biotite, Calcite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz, Silica
Compound Content
Fe, Mg
Ca, NaCl
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Properties
Physical Properties
Hardness
2-3
5-6
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Streak
Unknown
White
Porosity
Highly Porous
Highly Porous
Luster
Shiny
Subvitreous to Dull
Compressive Strength
5.80 N/mm2
31
Not Available
Cleavage
Perfect
Perfect
Toughness
Not Yet Found
2.1
Specific Gravity
3.4-3.9
Not Available
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
Not Available
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K
15
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat 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
Afghanistan, Indonesia, Japan, Russia
Africa
Cameroon, East Africa, Tanzania, Western Africa
Ethiopia, Kenya, Tanzania
Europe
United Kingdom
Greece, Hungary, Iceland, Italy, Turkey
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA
South America
Bolivia, Brazil, Colombia, Ecuador
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
New Zealand, Western Australia
All about Hornfels and Scoria Properties
Know all about Hornfels and Scoria properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Scoria belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Scoria is Vesicular. Hornfels appears Dull and Scoria appears Glassy and Vesicular. The luster of Hornfels is shiny while that of Scoria is subvitreous to dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Scoria is available in black, brown, dark grey to black, red colors. The commercial uses of Hornfels are cemetery markers, commemorative tablets, creating artwork and that of Scoria are as a traction material on snow-covered roads, creating artwork, high-temperature insulation, in gas barbecue grills.
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