Dacite

Arkose

Dacite and Arkose

Dacite

Arkose

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Definition

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

Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar

History

Origin

Romania and Moldova, Europe

France

Discoverer

Unknown

Alexandre Brongniart

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 Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Clastic

Color

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

Reddish Brown

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

Paving Stone, Office Buildings

Other Architectural Uses

Curbing

Whetstones

Industry

Construction Industry

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

Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Arkose

Features

Host Rock for Lead, Is one of the oldest rock

Available in Lots of Colors and Patterns, Generally rough to touch, 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.

Arkose rock forms from the weathering of feldspar-rich igneous or metamorphic rock, most commonly granitic rocks, which are primarily composed of quartz and feldspar.

Composition

Mineral Content

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

Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz

Compound Content

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

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-2.256-7

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Dull

Compressive Strength

70.00 N/mm²80.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.86-2.870

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.78 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

Africa

Namibia, Nigeria, South Africa

Europe

France, Greece, Romania, Scotland, Spain

Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom

Others

Greenland

Deposits in Western Continents

North America

USA

Canada, USA

South America

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

Brazil

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

New South Wales, New Zealand

All about Dacite and Arkose Properties

Know all about Dacite and Arkose properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Arkose belongs to Sedimentary Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Arkose is Clastic. Dacite appears Vesicular and Arkose appears Rough and Dull. The luster of Dacite is subvitreous to dull while that of Arkose is dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Arkose is available in reddish brown colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Arkose are in aquifers, soil conditioner, source of magnesia (mgo), tombstones.