Gneiss

Rhyolite

Gneiss and Rhyolite

Gneiss

Rhyolite

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1 Definition

1.1 Definition

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

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

1.2 History

1.2.1 Origin

Unknown

North America

1.2.2 Discoverer

Unknown

Ferdinand von Richthofen

1.3 Etymology

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

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

1.4 Class

Metamorphic Rocks

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Not Applicable

Volcanic

1.6 Other Categories

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Banded, Foliated, Platy

Aphanitic, Glassy, Porphyritic

2.2 Color

Black, Brown, Pink, Red, White

Grey, White, Light Black

2.3 Maintenance

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

81% Metamorphic Rocks Rocks have it !

✔ ✘

81% Igneous Rocks Rocks have it !

2.4.2 Scratch Resistant

✔ ✘

65% Metamorphic Rocks Rocks have it !

✔ ✘

86% Igneous Rocks Rocks have it !

2.4.3 Stain Resistant

✔ ✘

42% Metamorphic Rocks Rocks have it !

✔ ✘

66% Igneous Rocks Rocks have it !

2.4.4 Wind Resistant

✔ ✘

19% Metamorphic Rocks Rocks have it !

✔ ✘

49% Igneous Rocks Rocks have it !

2.4.5 Acid Resistant

✔ ✘

15% Metamorphic Rocks Rocks have it !

✔ ✘

48% Igneous Rocks Rocks have it !

2.5 Appearance

Foliated

Banded

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Countertops, Decorative Aggregates, Flooring, Interior Decoration

Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens

3.1.2 Exterior Uses

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

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

3.1.3 Other Architectural Uses

Curbing

Not Yet Used

3.2 Industry

3.2.1 Construction Industry

As Dimension Stone

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

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

Gemstone, Laboratory bench tops, Jewelry

4 Types

4.1 Types

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

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

4.2 Features

Generally rough to touch, Is one of the oldest rock

Acidic in nature, Available in lots of colors

4.3 Archaeological Significance

4.3.1 Monuments

Used

Not Yet Used

4.3.2 Famous Monuments

Konark Sun Temple in India, Washington Monument, US

Not Applicable

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

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.

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

5.2 Composition

5.2.1 Mineral Content

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

Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz

5.2.2 Compound Content

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

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

50% Metamorphic Rocks Rocks have it !

✔ ✘

97% Igneous Rocks Rocks have it !

5.3.2 Types of Metamorphism

Impact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

5.3.3 Weathering

✔ ✘

65% Metamorphic Rocks Rocks have it !

✔ ✘

99% Igneous Rocks Rocks have it !

5.3.4 Types of Weathering

Biological Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

77% Metamorphic Rocks Rocks have it !

✔ ✘

92% Igneous Rocks Rocks have it !

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6-7

6.1.2 Grain Size

Medium to Coarse Grained

Large and Coarse Grained

6.1.3 Fracture

Irregular

Sub-conchoidal

6.1.4 Streak

White

Colorless

6.1.5 Porosity

Very Less Porous

Highly Porous

6.1.6 Luster

Dull

Earthy

6.1.7 Compressive Strength

What Is Flint

⊕

▶

▼

125.00 N/mm²

Rank: 17 (Overall)▶

140.00 N/mm²

Rank: 15 (Overall)▶

▲

What Is Obsidian

⊕

▶

175 (What Is Grani..)

◀ ▶ ADD ⊕

6.1.8 Cleavage

Poor

Not Available

6.1.9 Toughness

1.2

6.1.10 Specific Gravity

2.5-2.7

2.65-2.67

6.1.11 Transparency

Translucent to Opaque

Opaque

6.1.12 Density

2.6-2.9 g/cm³

2.4-2.6 g/cm³

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

What Is Banded ..

⊕

▶

▼

Not Available

Rank: N/A (Overall)▶

Not Available

Rank: N/A (Overall)▶

▲

What Is Granulite

⊕

▶

1.09 (What Is Trave..)

◀ ▶ ADD ⊕

6.2.2 Resistance

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Heat Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

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

China, India

7.1.2 Africa

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

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

7.1.3 Europe

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

Germany, Iceland, Ireland, Italy, Spain

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

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

Canada, USA

7.2.2 South America

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

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, New Zealand, Queensland, Victoria

New Zealand, Queensland, Western Australia

All about Gneiss and Rhyolite Properties

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