Rhyolite

Comendite

Rhyolite and Comendite

Rhyolite

Comendite

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Definition

Rhyolite is a fine-grained igneous rock which is rich in silica

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

History

Origin

North America

Italy

Discoverer

Ferdinand von Richthofen

Unknown

Etymology

From German Rhyolit, from Greek rhuax lava stream + lithos stone

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Medium Grained Rock, Opaque Rock

Texture

Aphanitic, Glassy, Porphyritic

Porphyritic

Color

Grey, White, Light Black

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Banded

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives

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

Gemstone, Laboratory bench tops, Jewelry

Cemetery Markers

Types

Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.

Rhyolite

Features

Acidic in nature, Available in lots of colors

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

Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.

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

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Albite, Amphibole, Quartz

Compound Content

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

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6-76-7

1 7

👆🏻

Grain Size

Large and Coarse Grained

Medium Grained

Fracture

Sub-conchoidal

Pervasive

Streak

Bluish Black

Porosity

Highly Porous

Luster

Earthy

Dull

Compressive Strength

140.00 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.65-2.672.38

0 8.4

👆🏻

Transparency

Opaque

Density

2.4-2.6 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, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India

China

Africa

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

East Africa

Europe

Germany, Iceland, Ireland, Italy, Spain

Italy

Others

Deposits in Western Continents

North America

Canada, USA

South America

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

Deposits in Oceania Continent

Australia

New Zealand, Queensland, Western Australia

Queensland

All about Rhyolite and Comendite Properties

Know all about Rhyolite and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite and Comendite belong to Igneous Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Comendite is Porphyritic. Rhyolite appears Banded and Comendite appears Foliated. The luster of Rhyolite is earthy while that of Comendite is dull. Rhyolite is available in grey, white, light black colors whereas Comendite is available in blue, bluish - grey colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Comendite are cemetery markers.