Comendite

Dacite

Comendite and Dacite

Comendite

Dacite

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Definition

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

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

History

Origin

Italy

Romania and Moldova, Europe

Discoverer

Unknown

Etymology

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

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, Hard Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Medium Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Porphyritic

Aphanitic to Porphyritic

Color

Blue, Bluish - Grey

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Foliated

Vesicular

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

As Building Stone, Paving Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

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

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Cemetery Markers

Commemorative Tablets, Creating Artwork

Types

Rhyolite

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Features

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

Host Rock for Lead, Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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

Albite, Amphibole, Quartz

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

Compound Content

Al, Fe, Potassium Oxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Water Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

6-72-2.25

1 7

👆🏻

Grain Size

Medium Grained

Medium to Fine Coarse Grained

Fracture

Pervasive

Conchoidal

Streak

Bluish Black

White

Porosity

Highly Porous

Less Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

92.40 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.382.86-2.87

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

-9999 g/cm³2.77-2.771 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China

Africa

East Africa

Europe

Italy

France, Greece, Romania, Scotland, Spain

Others

Deposits in Western Continents

North America

USA

South America

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

Deposits in Oceania Continent

Australia

Queensland

New Zealand, South Australia, Western Australia

All about Comendite and Dacite Properties

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