Migmatite

Obsidian

Migmatite and Obsidian

Migmatite

Obsidian

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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

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth

History

Origin

Southern Alps, France

Ethiopia

Discoverer

Jakob Sederholm

Obsius

Etymology

From the Greek word migma which means a mixture

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

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

Opaque Rock

Texture

Foliated

Glassy

Color

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

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Banded and Foilated

Shiny

Uses

Architecture

Interior Uses

Countertops, Flooring, Kitchens

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts

Artifacts, Jewellery

Other Uses

Commercial Uses

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

Creating Artwork, Mirror, Used in aquariums

Types

Diatexites and Metatexites

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

Features

Generally rough to touch, Is one of the oldest rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

Composition

Mineral Content

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

Compound Content

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

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact 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, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

5.5-6.55-5.5

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Very Less Porous

Luster

Dull to Pearly to Subvitreous

Vitreous

Compressive Strength

120.00 N/mm²0.15 N/mm²

0.15 450

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Cleavage

Toughness

1.2

Specific Gravity

2.65-2.752.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

-9999 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Indonesia, Japan, Russia

Africa

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

Kenya

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

Greece, Hungary, Iceland, Italy, Turkey

Others

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

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria

New Zealand

All about Migmatite and Obsidian Properties

Know all about Migmatite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Migmatite belongs to Metamorphic Rocks while Obsidian belongs to Igneous Rocks.Texture of Migmatite is Foliated whereas that of Obsidian is Glassy. Migmatite appears Dull, Banded and Foilated and Obsidian appears Shiny. The luster of Migmatite is dull to pearly to subvitreous while that of Obsidian is vitreous. Migmatite is available in black, bluish - grey, brown, brown- black, dark greenish - grey, dark grey to black colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Migmatite are cemetery markers, jewelry, tombstones, used to manufracture paperweights and bookends and that of Obsidian are creating artwork, mirror, used in aquariums.