Rhyodacite

Comendite

Rhyodacite and Comendite

Rhyodacite

Comendite

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Definition

Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite

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

History

Origin

USA

Italy

Discoverer

Unknown

Etymology

Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Medium Grained Rock, Opaque Rock

Texture

Earthy

Porphyritic

Color

Black to Grey, Dark Greenish - Grey

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Skeletal

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

As Building 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

Cemetery Markers, Creating Artwork

Cemetery Markers

Types

Intermediate volcanic rock

Rhyolite

Features

Available in Lots of Colors and Patterns

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

Rhyodacite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

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, Potassium, Silicon Dioxide

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

5.5-66-7

1 7

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Grain Size

Fine Grained

Medium Grained

Fracture

Conchoidal

Pervasive

Streak

Black

Bluish Black

Porosity

Less Porous

Highly Porous

Luster

Greasy to Dull

Dull

Compressive Strength

200.50 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.1

Specific Gravity

2.34-2.402.38

0 8.4

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Transparency

Opaque

Density

-9999 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

1.12 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam

China

Africa

Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa

East Africa

Europe

Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland

Italy

Others

Deposits in Western Continents

North America

Canada, USA

South America

Deposits in Oceania Continent

Australia

Queensland

All about Rhyodacite and Comendite Properties

Know all about Rhyodacite and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Rhyodacite and Comendite belong to Igneous Rocks.Texture of Rhyodacite is Earthy whereas that of Comendite is Porphyritic. Rhyodacite appears Skeletal and Comendite appears Foliated. The luster of Rhyodacite is greasy to dull while that of Comendite is dull. Rhyodacite is available in black to grey, dark greenish - grey colors whereas Comendite is available in blue, bluish - grey colors. The commercial uses of Rhyodacite and Comendite are cemetery markers, creating artwork.