Dacite

Greywacke

Dacite and Greywacke

Dacite

Greywacke

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Definition

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

Greywacke is defined as a dark coarse-grained sandstone rock which contains more than 15 per cent clay

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 German Grauwacke, from grau grey + wacke

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

Fine Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Clastic

Color

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

Beige, Black, Brown, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Floor Tiles, Flooring, Homes, Interior Decoration

Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

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

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

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

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

As armour rock for sea walls, Petroleum reservoirs, Sea Defence, Tombstones

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Greywacke

Features

Host Rock for Lead, Is one of the oldest rock

Available in Lots of Colors and Patterns, Generally rough to touch, Non-vesicular, Veined

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.

Graywacke rock is a type of sedimentary rock, which is also known as immature sandstone, which is indurated, dark grey and consisting of poorly sorted angular to sub-angular, sand-sized grains.

Composition

Mineral Content

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

Augite, Biotite, Calcite, Chlorite, Clay, Clay Minerals, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz

Compound Content

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

Aluminium Oxide, NaCl, CaO, Chromium(III) Oxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Coastal Erosion, Sea Erosion, Wind Erosion

Properties

Physical Properties

Hardness

2-2.256-7

1 7

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Grain Size

Medium to Fine Coarse Grained

Angular and Fine

Fracture

Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Dull

Compressive Strength

70.00 N/mm²120.00 N/mm²

0.15 450

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Cleavage

Perfect

Toughness

2.6

Specific Gravity

2.86-2.872.2-2.8

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.77-2.771 g/cm³2.6-2.61 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.71 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 Greywacke Properties

Know all about Dacite and Greywacke properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Greywacke belongs to Sedimentary Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Greywacke is Clastic. Dacite appears Vesicular and Greywacke appears Dull. The luster of Dacite is subvitreous to dull while that of Greywacke is dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Greywacke is available in beige, black, brown, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Greywacke are as armour rock for sea walls, petroleum reservoirs, sea defence, tombstones.