Obsidian

Rhyolite

Obsidian and Rhyolite

Obsidian

Rhyolite

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1 Definition

1.1 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

1.2 History

1.2.1 Origin

Ethiopia

North America

1.2.2 Discoverer

Obsius

Ferdinand von Richthofen

1.3 Etymology

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

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

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Opaque Rock

Coarse Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Aphanitic, Glassy, Porphyritic

2.2 Color

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

Grey, White, Light Black

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

Shiny

Banded

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

3.1.2 Exterior Uses

Garden Decoration

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

3.1.3 Other Architectural Uses

Not Yet Used

3.2 Industry

3.2.1 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

3.2.2 Medical Industry

Surgery

Not Yet Used

3.3 Antiquity Uses

Artifacts, Jewellery

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Gemstone, Laboratory bench tops, Jewelry

4 Types

4.1 Types

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

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

4.2 Features

Blocks negativity, Helps to protect against depression

Acidic in nature, Available in lots of colors

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

4.3.2 Famous Monuments

Not Applicable

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.4.2 Figurines

Not Yet Used

4.5 Fossils

Absent

5 Formation

5.1 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.

5.2 Composition

5.2.1 Mineral Content

Not Available

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

5.2.2 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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.56-7

1 7

6.1.2 Grain Size

Not Applicable

Large and Coarse Grained

6.1.3 Fracture

Conchoidal

Sub-conchoidal

6.1.4 Streak

White

Colorless

6.1.5 Porosity

Very Less Porous

Highly Porous

6.1.6 Luster

Vitreous

Earthy

6.1.7 Compressive Strength

0.15 N/mm²140.00 N/mm²

0.15 450

7.3.2 Cleavage

Non-Existent

Not Available

7.3.3 Toughness

Not Available

7.3.4 Specific Gravity

2.6-2.72.65-2.67

0 8.4

7.3.5 Transparency

Translucent

Opaque

7.3.6 Density

2.6 g/cm³2.4-2.6 g/cm³

0 1400

7.4 Thermal Properties

7.4.1 Specific Heat Capacity

0.92 kJ/Kg KNA

0.14 3.2

7.4.2 Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Wear Resistant

8 Reserves

8.1 Deposits in Eastern Continents

8.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

China, India

8.1.2 Africa

Kenya

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

8.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Germany, Iceland, Ireland, Italy, Spain

8.1.4 Others

Not Yet Found

8.2 Deposits in Western Continents

8.2.1 North America

Canada, Mexico, USA

Canada, USA

8.2.2 South America

Argentina, Chile, Ecuador, Peru

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

8.3 Deposits in Oceania Continent

8.3.1 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.