Rhyolite

Gneiss

Rhyolite and Gneiss

Rhyolite

Gneiss

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1 Definition

1.1 Definition

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

Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks

1.2 History

1.2.1 Origin

North America

Unknown

1.2.2 Discoverer

Ferdinand von Richthofen

Unknown

1.3 Etymology

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

From the Middle High German verb gneist (to spark; so called because the rock glitters)

1.4 Class

Igneous Rocks

Metamorphic Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

Not Applicable

1.6 Other Categories

Coarse Grained Rock, Opaque Rock

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic, Glassy, Porphyritic

Banded, Foliated, Platy

2.2 Color

Grey, White, Light Black

Black, Brown, Pink, Red, White

2.3 Maintenance

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Banded

Foliated

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

Countertops, Decorative Aggregates, Flooring, Interior Decoration

3.1.2 Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

3.1.3 Other Architectural Uses

Not Yet Used

Curbing

3.2 Industry

3.2.1 Construction Industry

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

As Dimension Stone

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Gemstone, Laboratory bench tops, Jewelry

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

4 Types

4.1 Types

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

Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.

4.2 Features

Acidic in nature, Available in lots of colors

Generally rough to touch, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

Used

4.3.2 Famous Monuments

Not Applicable

Konark Sun Temple in India, Washington Monument, US

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Not Used

4.3.6 Petroglyphs

Not Used

4.3.7 Figurines

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 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.

Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.

5.2 Composition

5.2.1 Mineral Content

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

5.2.2 Compound Content

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

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Impact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6-77

1 7

6.1.2 Grain Size

Large and Coarse Grained

Medium to Coarse Grained

6.1.3 Fracture

Sub-conchoidal

Irregular

6.1.4 Streak

Colorless

White

6.1.5 Porosity

Highly Porous

Very Less Porous

6.1.6 Luster

Earthy

Dull

6.1.7 Compressive Strength

140.00 N/mm²125.00 N/mm²

0.15 450

6.1.8 Cleavage

Not Available

Poor

6.1.9 Toughness

1.2

6.1.10 Specific Gravity

2.65-2.672.5-2.7

0 8.4

6.1.11 Transparency

Opaque

Translucent to Opaque

6.1.12 Density

2.4-2.6 g/cm³2.6-2.9 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

NANA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

China, India

China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia

7.1.2 Africa

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

Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo

7.1.3 Europe

Germany, Iceland, Ireland, Italy, Spain

Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

Canada, Costa Rica, Cuba, Mexico, Panama, USA

7.2.2 South America

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

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, Queensland, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Rhyolite and Gneiss Properties

Know all about Rhyolite and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Rhyolite belongs to Igneous Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Rhyolite is Aphanitic, Glassy, Porphyritic whereas that of Gneiss is Banded, Foliated, Platy. Rhyolite appears Banded and Gneiss appears Foliated. The luster of Rhyolite is earthy while that of Gneiss is dull. Rhyolite is available in grey, white, light black colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Rhyolite are gemstone, laboratory bench tops, jewelry and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.