Rhyolite

Pseudotachylite

Rhyolite and Pseudotachylite

Rhyolite

Pseudotachylite

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1 Definition

1.1 Definition

Rhyolite is a fine-grained igneous rock which is rich in silica

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

1.2 History

1.2.1 Origin

North America

USA

1.2.2 Discoverer

Ferdinand von Richthofen

Unknown

1.3 Etymology

From German Rhyolit, from Greek rhuax lava stream + lithos stone

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

1.4 Class

Igneous Rocks

Metamorphic Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

Not Applicable

1.6 Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic, Glassy, Porphyritic

Quench

2.2 Color

Grey, White, Light Black

Black, Brown, Colourless, Green, Grey, Pink, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Banded

Dull and Soft

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Decorative Aggregates, Entryways, Interior Decoration

3.1.2 Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

3.1.3 Other Architectural Uses

Not Yet Used

Curbing

3.2 Industry

3.2.1 Construction Industry

Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives

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

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

Artifacts, Monuments

3.4 Other Uses

3.4.1 Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

Creating Artwork, Gemstone

4 Types

4.1 Types

Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.

Not Available

4.2 Features

Acidic in nature, Available in lots of colors

Host Rock for Lead

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

Used

4.3.2 Famous Monuments

Not Applicable

Data Not Available

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Not Used

4.3.6 Petroglyphs

Not Used

4.3.7 Figurines

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.

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.

5.2 Composition

5.2.1 Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

5.2.2 Compound Content

Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Not Applicable

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Not Applicable

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6-77

1 7

6.1.2 Grain Size

Large and Coarse Grained

Very fine-grained

6.1.3 Fracture

Sub-conchoidal

Uneven

6.1.4 Streak

Colorless

Light to dark brown

6.1.5 Porosity

Highly Porous

Less Porous

6.1.6 Luster

Earthy

Vitreous

6.1.7 Compressive Strength

140.00 N/mm²60.00 N/mm²

0.15 450

6.1.8 Cleavage

Not Available

Irregular

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.65-2.672.46-2.86

0 8.4

6.1.11 Transparency

Opaque

Transparent to Translucent

6.1.12 Density

2.4-2.6 g/cm³2.7-2.9 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

NA0.92 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Wear Resistant

Heat Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

China, India

South Korea

7.1.2 Africa

Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa

Western Africa

7.1.3 Europe

Germany, Iceland, Ireland, Italy, Spain

Great Britain, Switzerland

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

Not Yet Found

7.2.2 South America

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, Queensland, Western Australia

Central Australia, Western Australia

All about Rhyolite and Pseudotachylite Properties

Know all about Rhyolite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Pseudotachylite is Quench. Rhyolite appears Banded and Pseudotachylite appears Dull and Soft. The luster of Rhyolite is earthy while that of Pseudotachylite is vitreous. Rhyolite is available in grey, white, light black colors whereas Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Pseudotachylite are creating artwork, gemstone.