Dacite

Tachylite

Dacite and Tachylite

Dacite

Tachylite

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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

History

Origin

Romania and Moldova, Europe

Iceland

Discoverer

Unknown

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

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

Texture

Aphanitic to Porphyritic

Vitreous

Color

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

Black, Dark Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Glassy

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Cutting Tool, Knives, Landscaping, Scrapers

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

Cemetery Markers, Creating Artwork

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Volcanic glass

Features

Host Rock for Lead, Is one of the oldest rock

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Composition

Mineral Content

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

Feldspar, Olivine

Compound Content

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

Fe, Mg

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-2.255.5

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White

Vermilion

Porosity

Less Porous

Luster

Subvitreous to Dull

Resinous

Compressive Strength

70.00 N/mm²206.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.86-2.872.4

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³3.058 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.56 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Cambodia, Russia, South Korea

Africa

East Africa

Europe

France, Greece, Romania, Scotland, Spain

England, Germany, Hungary, Iceland, Scotland, Sweden

Others

Hawaii Islands

Deposits in Western Continents

North America

USA

South America

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

Deposits in Oceania Continent

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.