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
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
Origin
New Zealand
New Zealand
Discoverer
Unknown
Unknown
Etymology
From German which means hornstone
From Greek mulōn mill + -ite
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Granular, Platy
Foliated
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Black to Grey
Durability
Durable
Durable
Appearance
Dull
Dull, Banded and Foilated
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
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Roadstone
for Road Aggregate, Landscaping, Roadstone
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Creating Artwork, Gemstone, Jewelry
Types
Biotite hornfels
Blastomylonites, Ultramylonites and Phyllonites
Features
Smooth to touch
Surfaces are often shiny
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.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Mineral Content
Andalusite
Porphyroblasts
Compound Content
Fe, Mg
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Types of Metamorphism
-
-
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Highly Porous
Cleavage
Perfect
Conchoidal
Specific Gravity
3.4-3.9
2.97-3.05
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
2.6-4.8 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
China, India, Indonesia, Saudi Arabia, South Korea
Africa
Cameroon, East Africa, Tanzania, Western Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Europe
United Kingdom
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Deposits in Western Continents
North America
Canada, USA
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 Mylonite 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 Mylonite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Mylonite. Learn more about Hornfels vs Mylonite in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Mylonite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Hornfels and Mylonite, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Mylonite include For road aggregate, Landscaping, Roadstone.
More about Hornfels and Mylonite
Here you can know more about Hornfels and Mylonite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Mylonite consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Mylonite includes Porphyroblasts. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Mylonite, 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, Mylonite is available in black to grey colors. Appearance of Hornfels is Dull and that of Mylonite is Dull, Banded and Foilated. Properties of rock is another aspect for Hornfels vs Mylonite. The hardness of Hornfels is 2-3 and that of Mylonite is 3-4. The types of Hornfels are Biotite hornfels whereas types of Mylonite are Blastomylonites, Ultramylonites and Phyllonites. 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 Mylonite is white. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Mylonite is 1.50 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 Mylonite is heat resistant, impact resistant, pressure resistant.