Dacite

Tachylite

Dacite and Tachylite

Dacite

Tachylite

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1 Definition

1.1 Definition

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

Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt

1.2 History

1.2.1 Origin

Romania and Moldova, Europe

Iceland

1.2.2 Discoverer

Unknown

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 Tachylite, from tachy- + Greek lutos soluble, melting

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

Vitreous

2.2 Color

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

Black, Dark Brown

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

Glassy

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

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

Cutting Tool, Knives, Landscaping, Scrapers

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

Cemetery Markers, Creating Artwork

4 Types

4.1 Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Not Available

4.2 Features

Host Rock for Lead, Is one of the oldest rock

Available in Lots of Colors and Patterns, Clasts are smooth to touch, NA

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

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.

Tachylite 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

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

Feldspar, Olivine

5.2.2 Compound Content

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

Fe, Mg

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic 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

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-2.255.5

1 7

6.1.2 Grain Size

Medium to Fine Coarse Grained

6.1.3 Fracture

Conchoidal

6.1.4 Streak

White

Vermilion

6.1.5 Porosity

Less Porous

6.1.6 Luster

Subvitreous to Dull

Resinous

6.1.7 Compressive Strength

NA206.00 N/mm²

0.15 450

6.1.8 Cleavage

Perfect

Not Available

6.1.9 Toughness

Not Available

6.1.10 Specific Gravity

2.86-2.872.4

0 8.4

6.1.11 Transparency

Translucent

Opaque

6.1.12 Density

2.77-2.771 g/cm³3.058 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg K0.56 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

Cambodia, Russia, South Korea

7.1.2 Africa

Not Yet Found

East Africa

7.1.3 Europe

France, Greece, Romania, Scotland, Spain

England, Germany, Hungary, Iceland, Scotland, Sweden

7.1.4 Others

Not Yet Found

Hawaii Islands

7.2 Deposits in Western Continents

7.2.1 North America

USA

7.2.2 South America

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

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, South Australia, Western Australia

Victoria

All about Dacite and Tachylite Properties

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