Rhyolite

Obsidian

Rhyolite and Obsidian

Rhyolite

Obsidian

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Definition

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

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth

History

Origin

North America

Ethiopia

Discoverer

Ferdinand von Richthofen

Obsius

Etymology

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

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Opaque Rock

Texture

Aphanitic, Glassy, Porphyritic

Glassy

Color

Grey, White, Light Black

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Banded

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration

Other Architectural Uses

Industry

Construction Industry

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

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts

Artifacts, Jewellery

Other Uses

Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

Creating Artwork, Mirror, Used in aquariums

Types

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

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

Features

Acidic in nature, Available in lots of colors

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

Composition

Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Compound Content

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

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, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6-75-5.5

1 7

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Grain Size

Large and Coarse Grained

Fracture

Sub-conchoidal

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Earthy

Vitreous

Compressive Strength

140.00 N/mm²0.15 N/mm²

0.15 450

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Cleavage

Toughness

Specific Gravity

2.65-2.672.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.4-2.6 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India

Afghanistan, Indonesia, Japan, Russia

Africa

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

Kenya

Europe

Germany, Iceland, Ireland, Italy, Spain

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

Canada, USA

Canada, Mexico, USA

South America

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

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand, Queensland, Western Australia

New Zealand

All about Rhyolite and Obsidian Properties

Know all about Rhyolite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite and Obsidian belong to Igneous Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Obsidian is Glassy. Rhyolite appears Banded and Obsidian appears Shiny. The luster of Rhyolite is earthy while that of Obsidian is vitreous. Rhyolite is available in grey, white, light black colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Obsidian are creating artwork, mirror, used in aquariums.