Rhyolite

Dacite

Rhyolite and Dacite

Rhyolite

Dacite

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1 Definition

1.1 Definition

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

Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite

1.2 History

1.2.1 Origin

North America

Romania and Moldova, Europe

1.2.2 Discoverer

Ferdinand von Richthofen

Unknown

1.3 Etymology

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

From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic, Glassy, Porphyritic

Aphanitic to Porphyritic

2.2 Color

Grey, White, Light Black

Bluish - Grey, Brown, Grey, Light to Dark 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

Banded

Vesicular

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, Paving 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, Construction Aggregate, for Road Aggregate, Landscaping

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

Commemorative Tablets, Creating Artwork

4 Types

4.1 Types

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

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

4.2 Features

Acidic in nature, Available in lots of colors

Host Rock for Lead, Is one of the oldest rock

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

Not Used

Used

4.3.6 Petroglyphs

Not Used

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.

Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.

5.2 Composition

5.2.1 Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

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

5.2.2 Compound Content

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

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic 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, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6-72-2.25

1 7

6.1.2 Grain Size

Large and Coarse Grained

Medium to Fine Coarse Grained

6.1.3 Fracture

Sub-conchoidal

Conchoidal

6.1.4 Streak

Colorless

White

6.1.5 Porosity

Highly Porous

Less Porous

6.1.6 Luster

Earthy

Subvitreous to Dull

6.1.7 Compressive Strength

140.00 N/mm²NA

0.15 450

6.1.8 Cleavage

Not Available

Perfect

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.65-2.672.86-2.87

0 8.4

6.1.11 Transparency

Opaque

Translucent

6.1.12 Density

2.4-2.6 g/cm³2.77-2.771 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, Impact Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

China, India

Not Yet Found

7.1.2 Africa

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

Not Yet Found

7.1.3 Europe

Germany, Iceland, Ireland, Italy, Spain

France, Greece, Romania, Scotland, Spain

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

USA

7.2.2 South America

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, Queensland, Western Australia

New Zealand, South Australia, Western Australia

All about Rhyolite and Dacite Properties

Know all about Rhyolite and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite and Dacite belong to Igneous Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Dacite is Aphanitic to Porphyritic. Rhyolite appears Banded and Dacite appears Vesicular. The luster of Rhyolite is earthy while that of Dacite is subvitreous to dull. Rhyolite is available in grey, white, light black colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Dacite are commemorative tablets, creating artwork.