Trondhjemite

Obsidian

Trondhjemite and Obsidian

Trondhjemite

Obsidian

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Definition

Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites are sometimes known as plagiogranites.

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

Tonale, Italy

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From Trondheim, Norway

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Volcanic

Other Categories

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

Opaque Rock

Texture

Phaneritic

Glassy

Color

Black, Brown, Light to Dark Grey, White

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Banded and Foilated

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, Cobblestones, Construction Aggregate, for Road Aggregate

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Jewellery

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

Creating Artwork, Mirror, Used in aquariums

Types

Intermediate intrusive rock

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

Features

Is one of the oldest rock, Typically speckled black and white.

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

When alkali feldspar is extracted from granite, it changes to granitoid and later, it becomes trondhjemite with quartz as major mineral.

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

Albite, Amphibole, Apatite, Biotite, Feldspar, Hornblade, Ilmenite, Magnetite, Manganese Oxides, Olivine, Plagioclase, Pyroxene, Quartz, Sulfides, Titanite, Zircon

Compound Content

NaCl, CaO, MgO, Silicon 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, Contact Metamorphism, Impact 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, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6-75-5.5

1 7

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Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

Bluish Black

White

Porosity

Very Less Porous

Luster

Subvitreous to Dull

Vitreous

Compressive Strength

130.00 N/mm²0.15 N/mm²

0.15 450

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Cleavage

Toughness

2.1

Specific Gravity

2.86-32.6-2.7

0 8.4

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Transparency

Opaque

Translucent

Density

2.73 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Africa

Egypt

Kenya

Europe

Finland, Germany, Italy, Romania, Sweden, Turkey

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

New Zealand

All about Trondhjemite and Obsidian Properties

Know all about Trondhjemite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Trondhjemite and Obsidian belong to Igneous Rocks.Texture of Trondhjemite is Phaneritic whereas that of Obsidian is Glassy. Trondhjemite appears Banded and Foilated and Obsidian appears Shiny. The luster of Trondhjemite is subvitreous to dull while that of Obsidian is vitreous. Trondhjemite is available in black, brown, light to dark grey, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Trondhjemite are cemetery markers, creating artwork and that of Obsidian are creating artwork, mirror, used in aquariums.