Pseudotachylite

Variolite

Pseudotachylite and Variolite

Pseudotachylite

Variolite

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Definition

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

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

History

Origin

USA

France

Discoverer

Unknown

Etymology

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

From Latin varius, speckled, variegated

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Quench

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Color

Black, Brown, Green, Grey, Pink, White

Black, Brown, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone

Cemetery Markers, Creating Artwork

Types

Cataclastic rock

Metamorphic rock

Features

Host Rock for Lead

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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

Composition

Mineral Content

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Olivine, Plagioclase, Pyroxene

Compound Content

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

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

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

Uneven

Conchoidal

Streak

Light to dark brown

White to Grey

Porosity

Less Porous

Luster

Vitreous

Compressive Strength

60.00 N/mm²37.50 N/mm²

0.15 450

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Cleavage

Toughness

2.3

Specific Gravity

2.46-2.862.8-3

0 8.4

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Transparency

Transparent to Translucent

Opaque

Density

2.7-2.9 g/cm³2.9-3.1 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

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Resistance

Heat Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

South Korea

India, Russia

Africa

Western Africa

South Africa

Europe

Great Britain, Switzerland

Iceland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Pseudotachylite and Variolite Properties

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