Dacite

Argillite

Dacite and Argillite

Dacite

Argillite

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Definition

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

Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate

History

Origin

Romania and Moldova, Europe

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 Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Clastic, Polished

Color

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

Dark Grey to Black, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Rough and Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

As Building Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

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

Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

Fire resistant, Used to manufracture paperweights and bookends

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Metamorphic rock

Features

Host Rock for Lead, Is one of the oldest rock

Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.

Composition

Mineral Content

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

Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz

Compound Content

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

Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

2-2.252-3

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fine Grained

Fracture

Conchoidal

Conchoidal to Uneven

Streak

White

White to Grey

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Waxy and Dull

Compressive Strength

70.00 N/mm²-

0.15 450

👆🏻

Cleavage

Perfect

Slaty

Toughness

2.6

Specific Gravity

2.86-2.872.56-2.68

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³2.54-2.66 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Europe

France, Greece, Romania, Scotland, Spain

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Others

Deposits in Western Continents

North America

USA

South America

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

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

All about Dacite and Argillite Properties

Know all about Dacite and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Argillite belongs to Sedimentary Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Argillite is Clastic, Polished. Dacite appears Vesicular and Argillite appears Rough and Dull. The luster of Dacite is subvitreous to dull while that of Argillite is waxy and dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Argillite is available in dark grey to black, pink, red, white colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Argillite are fire resistant, used to manufracture paperweights and bookends.