Variolite

Pseudotachylite

Variolite and Pseudotachylite

Variolite

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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

Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.

History

Origin

France

USA

Discoverer

Unknown

Etymology

From Latin varius, speckled, variegated

From pseudo- +‎ tachylite, a glassy rock generated by frictional heat within faults.

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Quench

Color

Black, Brown, Light to Dark Grey

Black, Brown, Green, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

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

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

Creating Artwork, Gemstone

Types

Metamorphic rock

Cataclastic rock

Features

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

Host Rock for Lead

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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Compound Content

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

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal 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

Properties

Physical Properties

Hardness

1 7

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Grain Size

Very fine-grained

Fracture

Conchoidal

Uneven

Streak

White to Grey

Light to dark brown

Porosity

Less Porous

Luster

Vitreous

Compressive Strength

37.50 N/mm²60.00 N/mm²

0.15 450

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Cleavage

Toughness

2.3

Specific Gravity

2.8-32.46-2.86

0 8.4

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Transparency

Opaque

Transparent to Translucent

Density

2.9-3.1 g/cm³2.7-2.9 g/cm³

0 1400

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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

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

South Korea

Africa

South Africa

Western Africa

Europe

Iceland

Great Britain, Switzerland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Variolite and Pseudotachylite Properties

Know all about Variolite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Pseudotachylite is Quench. Variolite appears Dull and Soft and Pseudotachylite appears Dull and Soft. The luster of Variolite is while that of Pseudotachylite is vitreous. Variolite is available in black, brown, light to dark grey colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Pseudotachylite are creating artwork, gemstone.