Mylonite

Chert

Mylonite and Chert

Mylonite

Chert

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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

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

History

Origin

New Zealand

Discoverer

Unknown

Etymology

From Greek mulōn mill + -ite

From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Foliated

Banded, Rough

Color

Black to Grey

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Banded and Foilated

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Landscaping, Roadstone

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

Types

Blastomylonites, Ultramylonites and Phyllonites

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

Features

Surfaces are often shiny

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

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

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

Composition

Mineral Content

Porphyroblasts

Quartz, Silicon

Compound Content

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

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

3-46.5-7

1 7

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Grain Size

Fine Grained

Very fine-grained

Fracture

Conchoidal

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Shiny

Waxy and Dull

Compressive Strength

1.28 N/mm²450.00 N/mm²

0.15 450

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Cleavage

Conchoidal

Toughness

1.5

Specific Gravity

2.97-3.052.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.6-4.8 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

1.50 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Indonesia, Saudi Arabia, South Korea

China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

Eritrea, Ethiopia, Ghana, South Africa, Western Africa

Kenya, Morocco, South Africa, Tanzania

Europe

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

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Bolivia, Brazil

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New South Wales, Queensland, South Australia, Western Australia

All about Mylonite and Chert Properties

Know all about Mylonite and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Mylonite belongs to Metamorphic Rocks while Chert belongs to Sedimentary Rocks.Texture of Mylonite is Foliated whereas that of Chert is Banded, Rough. Mylonite appears Dull, Banded and Foilated and Chert appears Glassy or Pearly. The luster of Mylonite is shiny while that of Chert is waxy and dull. Mylonite is available in black to grey colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Mylonite are creating artwork, gemstone, jewelry and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.