Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
Discoverer
Unknown
Unknown
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From Greek mulōn mill + -ite
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Black, Brown, Green, Grey, Pink, White
Black to Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Dull, Banded and Foilated
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
for Road Aggregate, Landscaping, Roadstone
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments
Commercial Uses
Creating Artwork, Gemstone
Creating Artwork, Gemstone, Jewelry
Types
Cataclastic rock
Blastomylonites, Ultramylonites and Phyllonites
Features
Host Rock for Lead
Surfaces are often shiny
Archaeological Significance
Formation
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.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Porphyroblasts
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
-
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Sea Erosion, Wind Erosion
Grain Size
Very fine-grained
Fine Grained
Fracture
Uneven
Conchoidal
Streak
Light to dark brown
White
Porosity
Less Porous
Highly Porous
Specific Gravity
2.46-2.86
2.97-3.05
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
2.6-4.8 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
South Korea
China, India, Indonesia, Saudi Arabia, South Korea
Africa
Western Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Europe
Great Britain, Switzerland
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Deposits in Western Continents
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Central Australia, Western Australia
Pseudotachylite 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. Pseudotachylite vs Mylonite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Pseudotachylite and Properties of Mylonite. Learn more about Pseudotachylite vs Mylonite in the next section. The interior uses of Pseudotachylite include Decorative aggregates, Entryways and Interior decoration whereas the interior uses of Mylonite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Pseudotachylite and Mylonite, they have various applications in construction industry. The uses of Pseudotachylite in construction industry include As dimension stone, Cement manufacture, For road aggregate, Making natural cement and that of Mylonite include For road aggregate, Landscaping, Roadstone.
More about Pseudotachylite and Mylonite
Here you can know more about Pseudotachylite and Mylonite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Pseudotachylite and Mylonite consists of mineral content and compound content. The mineral content of Pseudotachylite includes Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides and mineral content of Mylonite includes Porphyroblasts. You can also check out the list of all Metamorphic Rocks. When we have to compare Pseudotachylite vs Mylonite, the texture, color and appearance plays an important role in determining the type of rock. Pseudotachylite is available in black, brown, green, grey, pink, white colors whereas, Mylonite is available in black to grey colors. Appearance of Pseudotachylite is Dull and Soft and that of Mylonite is Dull, Banded and Foilated. Properties of rock is another aspect for Pseudotachylite vs Mylonite. The hardness of Pseudotachylite is 7 and that of Mylonite is 3-4. The types of Pseudotachylite are Cataclastic rock 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 Pseudotachylite is light to dark brown while that of Mylonite is white. The specific heat capacity of Pseudotachylite is 0.92 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.Pseudotachylite is heat resistant whereas Mylonite is heat resistant, impact resistant, pressure resistant.