Variolite

Gneiss

Variolite and Gneiss

Variolite

Gneiss

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1 Definition

1.1 Definition

Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance

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

France

Unknown

1.2.2 Discoverer

Unknown

1.3 Etymology

From Latin varius, speckled, variegated

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

Opaque Rock

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Banded, Foliated, Platy

2.2 Color

Black, Brown, Light to Dark Grey

Black, Brown, Pink, Red, White

2.3 Maintenance

Less

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

Dull and Soft

Foliated

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Countertops, Decorative Aggregates, Flooring, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration, Office Buildings

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

As Dimension Stone

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Cemetery Markers, Creating Artwork

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

4 Types

4.1 Types

Not Available

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

4.2 Features

Has High structural resistance against erosion and climate, Very fine grained rock

Generally rough to touch, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

Konark Sun Temple in India, Washington Monument, US

4.3.3 Sculpture

Used

Not Yet Used

4.3.4 Famous Sculptures

Data Not Available

Not Applicable

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Used

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.

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

Olivine, Plagioclase, Pyroxene

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

5.2.2 Compound Content

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

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, Contact Metamorphism, Hydrothermal Metamorphism, Impact 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

Not Applicable

Chemical Erosion, Coastal Erosion, Sea Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

1 7

6.1.2 Grain Size

Not Applicable

Medium to Coarse Grained

6.1.3 Fracture

Conchoidal

Irregular

6.1.4 Streak

White to Grey

White

6.1.5 Porosity

Less Porous

Very Less Porous

6.1.6 Luster

Not Available

Dull

6.1.7 Compressive Strength

37.50 N/mm²125.00 N/mm²

0.15 450

6.1.8 Cleavage

Not Available

Poor

6.1.9 Toughness

2.3

1.2

6.1.10 Specific Gravity

2.8-32.5-2.7

0 8.4

6.1.11 Transparency

Opaque

Translucent to Opaque

6.1.12 Density

2.9-3.1 g/cm³2.6-2.9 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.84 kJ/Kg KNA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

India, Russia

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

7.1.2 Africa

South Africa

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

7.1.3 Europe

Iceland

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

Brazil

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

Not Yet Found

New South Wales, New Zealand, Queensland, Victoria

All about Variolite and Gneiss Properties

Know all about Variolite and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Gneiss is Banded, Foliated, Platy. Variolite appears Dull and Soft and Gneiss appears Foliated. The luster of Variolite is not available while that of Gneiss is dull. Variolite is available in black, brown, light to dark grey colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.