Rhyolite

Adakite

Rhyolite and Adakite

Rhyolite

Adakite

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Definition

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

Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs

History

Origin

North America

Adak, Aleutian Islands

Discoverer

Ferdinand von Richthofen

Defant and Drummond

Etymology

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

From Adak, Aleutian Islands

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Aphanitic, Glassy, Porphyritic

Porphyritic

Color

Grey, White, Light Black

Black, Brown, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Banded

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens

Exterior Uses

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

As Building Stone, As Facing Stone, Office Buildings

Other Architectural Uses

Whetstones

Industry

Construction Industry

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

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Medical Industry

Antiquity Uses

Artifacts

Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

Commemorative Tablets, Pottery, Used in aquariums

Types

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

Intermediate volcanic rock

Features

Acidic in nature, Available in lots of colors

Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained 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.

Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.

Composition

Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Olivine, Plagioclase, Pyroxene

Compound Content

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

Aluminium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Coastal Erosion, Sea Erosion, Water Erosion

Properties

Physical Properties

Hardness

6-73-4

1 7

👆🏻

Grain Size

Large and Coarse Grained

Fine to Medium Grained

Fracture

Sub-conchoidal

Conchoidal

Streak

Bluish Black

Porosity

Highly Porous

Less Porous

Luster

Earthy

Grainy, Pearly and Vitreous

Compressive Strength

140.00 N/mm²200.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.65-2.67-9999

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 K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India

India, Russia

Africa

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

Ethiopia, Somalia, South Africa

Europe

Germany, Iceland, Ireland, Italy, Spain

Iceland

Others

Deposits in Western Continents

North America

Canada, USA

South America

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

Brazil

Deposits in Oceania Continent

Australia

New Zealand, Queensland, Western Australia

All about Rhyolite and Adakite Properties

Know all about Rhyolite and Adakite properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite and Adakite belong to Igneous Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Adakite is Porphyritic. Rhyolite appears Banded and Adakite appears Dull and Soft. The luster of Rhyolite is earthy while that of Adakite is grainy, pearly and vitreous. Rhyolite is available in grey, white, light black colors whereas Adakite is available in black, brown, light to dark grey colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Adakite are commemorative tablets, pottery, used in aquariums.