Dacite

Rhyolite

Dacite and Rhyolite

Dacite

Rhyolite

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1 Definition

1.1 Definition

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

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

1.2 History

1.2.1 Origin

Romania and Moldova, Europe

North America

1.2.2 Discoverer

Unknown

Ferdinand von Richthofen

1.3 Etymology

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

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

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

Aphanitic, Glassy, Porphyritic

2.2 Color

Bluish - Grey, Brown, Grey, Light to Dark Grey

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

Vesicular

Banded

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

3.1.2 Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

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

3.1.3 Other Architectural Uses

Curbing

Not Yet Used

3.2 Industry

3.2.1 Construction Industry

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

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

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Commemorative Tablets, Creating Artwork

Gemstone, Laboratory bench tops, Jewelry

4 Types

4.1 Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

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

4.2 Features

Host Rock for Lead, Is one of the oldest rock

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

4.3.7 Figurines

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

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.

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

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

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

5.2.2 Compound Content

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

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

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-2.256-7

1 7

6.1.2 Grain Size

Medium to Fine Coarse Grained

Large and Coarse Grained

6.1.3 Fracture

Conchoidal

Sub-conchoidal

6.1.4 Streak

White

Colorless

6.1.5 Porosity

Less Porous

Highly Porous

6.1.6 Luster

Subvitreous to Dull

Earthy

6.1.7 Compressive Strength

NA140.00 N/mm²

0.15 450

6.1.8 Cleavage

Perfect

Not Available

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.86-2.872.65-2.67

0 8.4

6.1.11 Transparency

Translucent

Opaque

6.1.12 Density

2.77-2.771 g/cm³2.4-2.6 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg KNA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

China, India

7.1.2 Africa

Not Yet Found

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

7.1.3 Europe

France, Greece, Romania, Scotland, Spain

Germany, Iceland, Ireland, Italy, Spain

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

USA

Canada, 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, South Australia, Western Australia

New Zealand, Queensland, Western Australia

All about Dacite and Rhyolite Properties

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