Dacite

Comendite

Dacite and Comendite

Dacite

Comendite

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Definition

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

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

History

Origin

Romania and Moldova, Europe

Italy

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

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Medium Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Porphyritic

Color

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

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

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

Other Uses

Commercial Uses

Commemorative Tablets, Creating Artwork

Cemetery Markers

Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Rhyolite

Features

Host Rock for Lead, Is one of the oldest rock

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

Absent

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.

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

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

Albite, Amphibole, Quartz

Compound Content

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

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

2-2.256-7

1 7

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Grain Size

Medium to Fine Coarse Grained

Medium Grained

Fracture

Conchoidal

Pervasive

Streak

White

Bluish Black

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Dull

Compressive Strength

70.00 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

2.86-2.872.38

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 K0.79 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

China

Africa

East Africa

Europe

France, Greece, Romania, Scotland, Spain

Italy

Others

Deposits in Western Continents

North America

USA

South America

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

Deposits in Oceania Continent

Australia

New Zealand, South Australia, Western Australia

Queensland

All about Dacite and Comendite Properties

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