Tachylite

Dacite

Tachylite and Dacite

Tachylite

Dacite

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Definition

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

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

History

Origin

Iceland

Romania and Moldova, Europe

Discoverer

Unknown

Etymology

From German Tachylite, from tachy- + Greek lutos soluble, melting

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

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

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Vitreous

Aphanitic to Porphyritic

Color

Black, Dark Brown

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

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

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Cutting Tool, Knives, Landscaping, Scrapers

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

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

Commemorative Tablets, Creating Artwork

Types

Volcanic glass

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Features

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

Host Rock for Lead, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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.

Composition

Mineral Content

Feldspar, Olivine

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

Compound Content

Fe, Mg

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

5.52-2.25

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

Vermilion

White

Porosity

Less Porous

Luster

Resinous

Subvitreous to Dull

Compressive Strength

206.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.42.86-2.87

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

3.058 g/cm³2.77-2.771 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.56 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Cambodia, Russia, South Korea

Africa

East Africa

Europe

England, Germany, Hungary, Iceland, Scotland, Sweden

France, Greece, Romania, Scotland, Spain

Others

Hawaii Islands

Deposits in Western Continents

North America

USA

South America

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

Deposits in Oceania Continent

Australia

Victoria

New Zealand, South Australia, Western Australia

All about Tachylite and Dacite Properties

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