Greywacke

Comendite

Greywacke and Comendite

Greywacke

Comendite

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Definition

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

Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite

History

Origin

Italy

Discoverer

Unknown

Etymology

From German Grauwacke, from grau grey + wacke

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Medium Grained Rock, Opaque Rock

Texture

Clastic

Porphyritic

Color

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

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Foliated

Uses

Architecture

Interior Uses

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

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing, Whetstones

Curbing

Industry

Construction Industry

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

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

Medical Industry

Antiquity Uses

Artifacts, Sculpture, Small Figurines

Artifacts

Other Uses

Commercial Uses

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

Cemetery Markers

Types

Greywacke

Rhyolite

Features

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

Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

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.

Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

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

Albite, Amphibole, Quartz

Compound Content

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

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Sea Erosion, Wind Erosion

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6-76-7

1 7

👆🏻

Grain Size

Angular and Fine

Medium Grained

Fracture

Conchoidal

Pervasive

Streak

White

Bluish Black

Porosity

Highly Porous

Luster

Dull

Compressive Strength

120.00 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.6

Specific Gravity

2.2-2.82.38

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.61 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

China

Africa

Namibia, Nigeria, South Africa

East Africa

Europe

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

Italy

Others

Greenland

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand

Queensland

All about Greywacke and Comendite Properties

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