Migmatite

Chert

Migmatite and Chert

Migmatite

Chert

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Definition

Migmatite is typically a granitic rock within a metamorphic host rock which is composed of two intermingled but distinguishable components

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

History

Origin

Southern Alps, France

Discoverer

Jakob Sederholm

Unknown

Etymology

From the Greek word migma which means a mixture

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

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Foliated

Banded, Rough

Color

Black, Bluish - Grey, Brown, Brown- Black, Dark Greenish - Grey, Dark Grey to Black

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

Countertops, Flooring, Kitchens

Decorative Aggregates, Homes

Exterior Uses

As Building Stone, As Facing Stone

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments

Other Uses

Commercial Uses

Cemetery Markers, Jewelry, Tombstones, Used to manufracture paperweights and bookends

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

Types

Diatexites and Metatexites

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

Features

Generally rough to touch, Is one of the oldest rock

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

Migmatites form by high temperature regional and thermal metamorphism of protolith rocks where rocks melt partially due to high temperature.

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

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

Quartz, Silicon

Compound Content

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

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

5.5-6.56.5-7

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Very fine-grained

Fracture

Irregular

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Dull to Pearly to Subvitreous

Waxy and Dull

Compressive Strength

120.00 N/mm²450.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.2

1.5

Specific Gravity

2.65-2.752.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

-9999 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

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

Africa

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

Kenya, Morocco, South Africa, Tanzania

Europe

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

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

Canada, Mexico, USA

South America

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

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria

New South Wales, Queensland, South Australia, Western Australia

All about Migmatite and Chert Properties

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