Definition
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks
  
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
  
History
  
  
Origin
Unknown
  
New Zealand
  
Discoverer
Unknown
  
Unknown
  
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
  
From Greek mulōn mill + -ite
  
Class
Metamorphic Rocks
  
Metamorphic Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Not Applicable
  
Not Applicable
  
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Banded, Foliated, Platy
  
Foliated
  
Color
Black, Brown, Pink, Red, White
  
Black to Grey
  
Maintenance
More
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
No
  
Wind Resistant
Yes
  
No
  
Acid Resistant
No
  
No
  
Appearance
Foliated
  
Dull, Banded and Foilated
  
Architecture
  
  
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
  
Decorative Aggregates, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
  
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone
  
for Road Aggregate, Landscaping, Roadstone
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts, Monuments
  
Other Uses
  
  
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
  
Creating Artwork, Gemstone, Jewelry
  
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
  
Blastomylonites, Ultramylonites and Phyllonites
  
Features
Generally rough to touch, Is one of the oldest rock
  
Surfaces are often shiny
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Konark Sun Temple in India, Washington Monument, US
  
Data Not Available
  
Sculpture
Not Yet Used
  
Used
  
Famous Sculptures
Not Applicable
  
Data Not Available
  
Pictographs
Not Used
  
Used
  
Petroglyphs
Not Used
  
Used
  
Figurines
Not Yet Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.
  
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
  
Composition
  
  
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
  
Porphyroblasts
  
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
No
  
Types of Metamorphism
Impact Metamorphism
  
Not Applicable
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
  
Chemical Erosion, Sea Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
7
  
3-4
  
Grain Size
Medium to Coarse Grained
  
Fine Grained
  
Fracture
Irregular
  
Conchoidal
  
Streak
White
  
White
  
Porosity
Very Less Porous
  
Highly Porous
  
Luster
Dull
  
Shiny
  
Compressive Strength
125.00 N/mm2
  
17
Cleavage
Poor
  
Conchoidal
  
Toughness
1.2
  
Not Available
  
Specific Gravity
2.5-2.7
  
2.97-3.05
  
Transparency
Translucent to Opaque
  
Opaque
  
Density
2.6-2.9 g/cm3
  
2.6-4.8 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
Not Available
  
1.50 kJ/Kg K
  
3
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant
  
Deposits in Eastern Continents
  
  
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
  
China, India, Indonesia, Saudi Arabia, South Korea
  
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
  
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
  
Europe
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom
  
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
  
USA
  
South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Queensland, Victoria
  
Central Australia, Western Australia
  
Gneiss 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. Gneiss vs Mylonite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Gneiss and Properties of Mylonite. Learn more about Gneiss vs Mylonite in the next section. The interior uses of Gneiss include Countertops, Decorative aggregates, Flooring and Interior decoration whereas the interior uses of Mylonite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Gneiss and Mylonite, they have various applications in construction industry. The uses of Gneiss in construction industry include As dimension stone and that of Mylonite include For road aggregate, Landscaping, Roadstone.
More about Gneiss and Mylonite
Here you can know more about Gneiss and Mylonite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Gneiss and Mylonite consists of mineral content and compound content. The mineral content of Gneiss includes Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon and mineral content of Mylonite includes Porphyroblasts. You can also check out the list of all Metamorphic Rocks. When we have to compare Gneiss vs Mylonite, the texture, color and appearance plays an important role in determining the type of rock. Gneiss is available in black, brown, pink, red, white colors whereas, Mylonite is available in black to grey colors. Appearance of Gneiss is Foliated and that of Mylonite is Dull, Banded and Foilated. Properties of rock is another aspect for Gneiss vs Mylonite. The hardness of Gneiss is 7 and that of Mylonite is 3-4. The types of Gneiss are Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss. 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 Gneiss and Mylonite is white. The specific heat capacity of Gneiss is Not Available 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.Gneiss is heat resistant, pressure resistant, scratch resistant, wear resistant whereas Mylonite is heat resistant, impact resistant, pressure resistant.