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
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
Unknown
Unknown
Etymology
From German which means hornstone
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
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
Quench
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black, Brown, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Dull
Dull and Soft
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
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Roadstone
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone
Types
Biotite hornfels
Cataclastic rock
Features
Smooth to touch
Host Rock for Lead
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. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Andalusite
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Fe, Mg
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering
-
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
-
Grain Size
Fine Grained
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
-
Light to dark brown
Porosity
Highly Porous
Less Porous
Specific Gravity
3.4-3.9
2.46-2.86
Transparency
Opaque
Transparent to Translucent
Density
0.25-0.30 g/cm3
2.7-2.9 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
South Korea
Africa
Cameroon, East Africa, Tanzania, Western Africa
Western Africa
Europe
United Kingdom
Great Britain, Switzerland
Deposits in Western Continents
North America
Canada, USA
-
South America
Bolivia, Brazil, Colombia, Ecuador
-
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
Central Australia, Western Australia
Hornfels vs Pseudotachylite 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 Pseudotachylite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Pseudotachylite. Learn more about Hornfels vs Pseudotachylite in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Pseudotachylite include Decorative aggregates, Entryways and Interior decoration. Due to some exceptional properties of Hornfels and Pseudotachylite, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Pseudotachylite include As dimension stone, Cement manufacture, For road aggregate, Making natural cement.
More about Hornfels and Pseudotachylite
Here you can know more about Hornfels and Pseudotachylite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Pseudotachylite consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Pseudotachylite includes Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Pseudotachylite, 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, Pseudotachylite is available in black, brown, green, grey, pink, white colors. Appearance of Hornfels is Dull and that of Pseudotachylite is Dull and Soft. Properties of rock is another aspect for Hornfels vs Pseudotachylite. The hardness of Hornfels is 2-3 and that of Pseudotachylite is 7. The types of Hornfels are Biotite hornfels whereas types of Pseudotachylite are Cataclastic rock. 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 Pseudotachylite is light to dark brown. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Pseudotachylite 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 Pseudotachylite is heat resistant.