Obsidian

Rhyolite

Obsidian and Rhyolite

Obsidian

Rhyolite

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Definition

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

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

History

Origin

Ethiopia

North America

Discoverer

Obsius

Ferdinand von Richthofen

Etymology

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

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Glassy

Aphanitic, Glassy, Porphyritic

Color

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

Grey, White, Light Black

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Exterior Uses

Garden Decoration

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

Other Architectural Uses

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

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

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Gemstone, Laboratory bench tops, Jewelry

Types

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

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

Features

Blocks negativity, Helps to protect against depression

Acidic in nature, Available in lots of colors

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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

Composition

Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Compound Content

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

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

5-5.56-7

1 7

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Grain Size

Large and Coarse Grained

Fracture

Conchoidal

Sub-conchoidal

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Vitreous

Earthy

Compressive Strength

0.15 N/mm²140.00 N/mm²

0.15 450

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Cleavage

Toughness

Specific Gravity

2.6-2.72.65-2.67

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.6 g/cm³2.4-2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.71 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

China, India

Africa

Kenya

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

Europe

Greece, Hungary, Iceland, Italy, Turkey

Germany, Iceland, Ireland, Italy, Spain

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, USA

South America

Argentina, Chile, Ecuador, Peru

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

Deposits in Oceania Continent

Australia

New Zealand

New Zealand, Queensland, Western Australia

All about Obsidian and Rhyolite Properties

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