Mylonite

Gneiss

Mylonite and Gneiss

Mylonite

Gneiss

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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

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

History

Origin

New Zealand

Discoverer

Unknown

Etymology

From Greek mulōn mill + -ite

From the Middle High German verb gneist (to spark; so called because the rock glitters)

Class

Metamorphic Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Foliated

Banded, Foliated, Platy

Color

Black to Grey

Black, Brown, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Banded and Foilated

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, Flooring, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Paving Stone, Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Landscaping, Roadstone

As Dimension Stone

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

Types

Blastomylonites, Ultramylonites and Phyllonites

Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.

Features

Surfaces are often shiny

Generally rough to touch, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Konark Sun Temple in India, Washington Monument, US

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.

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.

Composition

Mineral Content

Porphyroblasts

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

Compound Content

Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Impact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Properties

Physical Properties

Hardness

3-47

1 7

👆🏻

Grain Size

Fine Grained

Medium to Coarse Grained

Fracture

Conchoidal

Irregular

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Shiny

Dull

Compressive Strength

1.28 N/mm²125.00 N/mm²

0.15 450

👆🏻

Cleavage

Conchoidal

Toughness

1.2

Specific Gravity

2.97-3.052.5-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.6-4.8 g/cm³2.6-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

1.50 kJ/Kg K0.70 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Indonesia, Saudi Arabia, South Korea

China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia

Africa

Eritrea, Ethiopia, Ghana, South Africa, Western Africa

Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo

Europe

England, Finland, France, Germany, Great Britain, Greece, United Kingdom

Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada, Costa Rica, Cuba, Mexico, Panama, USA

South America

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Mylonite and Gneiss Properties

Know all about Mylonite and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Mylonite and Gneiss belong to Metamorphic Rocks.Texture of Mylonite is Foliated whereas that of Gneiss is Banded, Foliated, Platy. Mylonite appears Dull, Banded and Foilated and Gneiss appears Foliated. The luster of Mylonite is shiny while that of Gneiss is dull. Mylonite is available in black to grey colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Mylonite are creating artwork, gemstone, jewelry and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.