Definition
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.
Origin
New Zealand
Tonale, Italy
Discoverer
Unknown
Unknown
Etymology
From Greek mulōn mill + -ite
From Trondheim, Norway
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated
Phaneritic
Color
Black to Grey
Black, Brown, Light to Dark Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull, Banded and Foilated
Banded and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Landscaping, Roadstone
As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Cemetery Markers, Creating Artwork
Types
Blastomylonites, Ultramylonites and Phyllonites
Intermediate intrusive rock
Features
Surfaces are often shiny
Is one of the oldest rock, Typically speckled black and white.
Archaeological Significance
Formation
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.
Mineral Content
Porphyroblasts
Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon
Compound Content
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
NaCl, CaO, MgO, Silicon Dioxide
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White
Bluish Black
Porosity
Highly Porous
Very Less Porous
Luster
Shiny
Subvitreous to Dull
Specific Gravity
2.97-3.05
2.86-3
Transparency
Opaque
Opaque
Density
2.6-4.8 g/cm3
2.73 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Saudi Arabia, South Korea
-
Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Egypt
Europe
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Finland, Germany, Italy, Romania, Sweden, Turkey
Deposits in Western Continents
South America
-
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New Zealand, South Australia, Western Australia
Mylonite vs Trondhjemite 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. Mylonite vs Trondhjemite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Mylonite and Properties of Trondhjemite. Learn more about Mylonite vs Trondhjemite in the next section. The interior uses of Mylonite include Decorative aggregates and Interior decoration whereas the interior uses of Trondhjemite include Decorative aggregates, Entryways, Flooring, Homes and Interior decoration. Due to some exceptional properties of Mylonite and Trondhjemite, they have various applications in construction industry. The uses of Mylonite in construction industry include For road aggregate, Landscaping, Roadstone and that of Trondhjemite include As dimension stone, Cement manufacture, Cobblestones, Construction aggregate, For road aggregate.
More about Mylonite and Trondhjemite
Here you can know more about Mylonite and Trondhjemite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Mylonite and Trondhjemite consists of mineral content and compound content. The mineral content of Mylonite includes Porphyroblasts and mineral content of Trondhjemite includes Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon. You can also check out the list of all Metamorphic Rocks. When we have to compare Mylonite vs Trondhjemite, the texture, color and appearance plays an important role in determining the type of rock. Mylonite is available in black to grey colors whereas, Trondhjemite is available in black, brown, light to dark grey, white colors. Appearance of Mylonite is Dull, Banded and Foilated and that of Trondhjemite is Banded and Foilated. Properties of rock is another aspect for Mylonite vs Trondhjemite. The hardness of Mylonite is 3-4 and that of Trondhjemite is 6-7. The types of Mylonite are Blastomylonites, Ultramylonites and Phyllonites whereas types of Trondhjemite are Intermediate intrusive rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Mylonite is white while that of Trondhjemite is bluish black. The specific heat capacity of Mylonite is 1.50 kJ/Kg K and that of Trondhjemite 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.Mylonite is heat resistant, impact resistant, pressure resistant whereas Trondhjemite is heat resistant, pressure resistant, wear resistant.