Obsidian

Rhyodacite

Obsidian and Rhyodacite

Obsidian

Rhyodacite

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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

Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite

1.2 History

1.2.1 Origin

Ethiopia

USA

1.2.2 Discoverer

Obsius

Unknown

1.3 Etymology

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

Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy

Earthy

2.2 Color

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

Black to Grey, Dark Greenish - Grey

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

Skeletal

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration

As Building Stone, Garden Decoration

3.1.3 Other Architectural Uses

Not Yet Used

Curbing

3.2 Industry

3.2.1 Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping

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

Cemetery Markers, Creating Artwork

4 Types

4.1 Types

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

Not Available

4.2 Features

Blocks negativity, Helps to protect against depression

Available in Lots of Colors and Patterns

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

4.3.6 Petroglyphs

Used

4.3.7 Figurines

Not Yet Used

4.4 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.

Rhyodacite 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.

5.2 Composition

5.2.1 Mineral Content

Not Available

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon

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, NA, Potassium, Silicon Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact 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

6 Properties

6.1 Physical Properties

6.1.1 Hardness

5-5.55.5-6

1 7

6.1.2 Grain Size

Not Applicable

Fine Grained

6.1.3 Fracture

Conchoidal

6.1.4 Streak

White

Black

6.1.5 Porosity

Very Less Porous

Less Porous

6.1.6 Luster

Vitreous

Greasy to Dull

6.1.7 Compressive Strength

0.15 N/mm²200.50 N/mm²

0.15 450

6.1.8 Cleavage

Non-Existent

Not Available

6.1.9 Toughness

Not Available

2.1

6.1.10 Specific Gravity

2.6-2.72.34-2.40

0 8.4

6.1.11 Transparency

Translucent

Opaque

6.1.12 Density

2.6 g/cm³Not Available

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg K1.12 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant

Heat Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Indonesia, Japan, Russia

China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam

7.1.2 Africa

Kenya

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

7.1.3 Europe

Greece, Hungary, Iceland, Italy, Turkey

Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Canada, USA

7.2.2 South America

Argentina, Chile, Ecuador, Peru

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand

Not Yet Found

All about Obsidian and Rhyodacite Properties

Know all about Obsidian and Rhyodacite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Rhyodacite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Rhyodacite is Earthy. Obsidian appears Shiny and Rhyodacite appears Skeletal. The luster of Obsidian is vitreous while that of Rhyodacite is greasy to dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Rhyodacite is available in black to grey, dark greenish - grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Rhyodacite are cemetery markers, creating artwork.