Pseudotachylite

Felsite

Pseudotachylite and Felsite

Pseudotachylite

Felsite

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Definition

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

Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition

History

Origin

USA

Discoverer

Unknown

Etymology

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

From English feldspar and -ite

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Quench

Arborescent Patterned, Vitreous

Color

Black, Brown, Green, 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

Dull and Soft

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Flooring, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone

Mirror, Jewelry

Types

Cataclastic rock

Igneous rock

Features

Host Rock for Lead

Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, 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.

Felsite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Feldspar, Iron Oxides

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, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Glacier Erosion, Water Erosion

Properties

Physical Properties

Hardness

75-5.5

1 7

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Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven

Conchoidal

Streak

Light to dark brown

White

Porosity

Less Porous

Very Less Porous

Luster

Vitreous

Compressive Strength

60.00 N/mm²0.15 N/mm²

0.15 450

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Cleavage

Toughness

Specific Gravity

2.46-2.862.6-2.7

0 8.4

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Transparency

Transparent to Translucent

Translucent

Density

2.7-2.9 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

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

South Korea

Afghanistan, Indonesia, Japan, Russia

Africa

Western Africa

Kenya

Europe

Great Britain, Switzerland

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New Zealand

All about Pseudotachylite and Felsite Properties

Know all about Pseudotachylite and Felsite properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Felsite belongs to Igneous Rocks.Texture of Pseudotachylite is Quench whereas that of Felsite is Arborescent Patterned, Vitreous. Pseudotachylite appears Dull and Soft and Felsite appears Layered, Banded, Veined and Shiny. The luster of Pseudotachylite and Felsite is vitreous. Pseudotachylite is available in black, brown, green, grey, pink, white colors whereas Felsite is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Pseudotachylite are creating artwork, gemstone and that of Felsite are mirror, jewelry.