Variolite

Trondhjemite

Variolite and Trondhjemite

Variolite

Trondhjemite

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Definition

Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance

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.

History

Origin

France

Tonale, Italy

Discoverer

Unknown

Etymology

From Latin varius, speckled, variegated

From Trondheim, Norway

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Plutonic

Other Categories

Opaque Rock

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

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Phaneritic

Color

Black, Brown, Light to Dark Grey

Black, Brown, Light to Dark Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Banded and Foilated

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

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

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

Types

Metamorphic rock

Intermediate intrusive rock

Features

Has High structural resistance against erosion and climate, Very fine grained rock

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.

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

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

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

Compound Content

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

NaCl, CaO, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional 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

Properties

Physical Properties

Hardness

66-7

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White to Grey

Bluish Black

Porosity

Less Porous

Very Less Porous

Luster

Subvitreous to Dull

Compressive Strength

37.50 N/mm²130.00 N/mm²

0.15 450

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Cleavage

Toughness

2.3

2.1

Specific Gravity

2.8-32.86-3

0 8.4

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Transparency

Opaque

Density

2.9-3.1 g/cm³2.73 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, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Africa

South Africa

Egypt

Europe

Iceland

Finland, Germany, Italy, Romania, Sweden, Turkey

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Brazil

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

All about Variolite and Trondhjemite Properties

Know all about Variolite and Trondhjemite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite and Trondhjemite belong to Igneous Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Trondhjemite is Phaneritic. Variolite appears Dull and Soft and Trondhjemite appears Banded and Foilated. The luster of Variolite is while that of Trondhjemite is subvitreous to dull. Variolite is available in black, brown, light to dark grey colors whereas Trondhjemite is available in black, brown, light to dark grey, white colors. The commercial uses of Variolite and Trondhjemite are cemetery markers, creating artwork.