Anorthosite

Obsidian

Anorthosite and Obsidian

Anorthosite

Obsidian

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Definition

Anorthosite is a granular igneous rock composed largely of labradorite or plagioclase

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

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From French anorthose plagioclase + -ite1

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Opaque Rock

Texture

Foliated, Glassy

Glassy

Color

Black, Bluish - Grey, Brown, Green, Grey, Light Greenish Grey, Pink, White

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered, Banded, Veined and Shiny

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, for Road Aggregate

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Sculpture, Small Figurines

Artifacts, Jewellery

Other Uses

Commercial Uses

Creating Artwork, Curling

Creating Artwork, Mirror, Used in aquariums

Types

Proterozoic Anorthosite and Archean Anorthosite

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

Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal mafic component.

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

Amphibole, Clinopyroxene, Ilmenite, Magnetite, Olivine, Orthopyroxene

Compound Content

Ca, CaO, Chromium(III) Oxide, MgO, Sulfur Trioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

5-65-5.5

1 7

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Grain Size

Coarse Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Less Porous

Very Less Porous

Luster

Pearly to Subvitreous

Vitreous

Compressive Strength

180.00 N/mm²0.15 N/mm²

0.15 450

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Cleavage

Toughness

Specific Gravity

2.62-2.822.6-2.7

0 8.4

👆🏻

Transparency

Translucent

Density

2.7-4 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya

Europe

Bulgaria, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Malta, Poland, Portugal, Romania, Slovenia, Spain, Sweden, The Czech Republic

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

Canada

Canada, Mexico, USA

South America

Bolivia, Colombia

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

Central Australia, South Australia, Western Australia

New Zealand

All about Anorthosite and Obsidian Properties

Know all about Anorthosite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Anorthosite and Obsidian belong to Igneous Rocks.Texture of Anorthosite is Foliated, Glassy whereas that of Obsidian is Glassy. Anorthosite appears Layered, Banded, Veined and Shiny and Obsidian appears Shiny. The luster of Anorthosite is pearly to subvitreous while that of Obsidian is vitreous. Anorthosite is available in black, bluish - grey, brown, green, grey, light greenish grey, pink, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Anorthosite are creating artwork, curling and that of Obsidian are creating artwork, mirror, used in aquariums.