Variolite

Nephelinite

Variolite and Nephelinite

Variolite

Nephelinite

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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

Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).

1.2 History

1.2.1 Origin

France

Brazil

1.2.2 Discoverer

Unknown

1.3 Etymology

From Latin varius, speckled, variegated

from French néphéline, from Greek nephelē

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

Plutonic

1.6 Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Aphanitic

2.2 Color

Black, Brown, Light to Dark Grey

Black, Brown, Colourless, Green, Grey, 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

Skeletal

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Homes, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration, Office Buildings

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, 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, Cement Manufacture, Construction Aggregate, for Road Aggregate

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments, Sculpture, Small Figurines

3.4 Other Uses

3.4.1 Commercial Uses

Cemetery Markers, Creating Artwork

Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)

4 Types

4.1 Types

Not Available

Peralkaline Nephelinite

4.2 Features

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

Host Rock for Lead

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

4.3.3 Sculpture

Used

4.3.4 Famous Sculptures

Data Not Available

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

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.

Nephelinite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

5.2 Composition

5.2.1 Mineral Content

Olivine, Plagioclase, Pyroxene

Clinopyroxene, Nepheline, Plagioclase

5.2.2 Compound Content

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

Ca, CaO, Carbon, Cl, MgO

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

Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Not Applicable

Chemical Erosion, Water Erosion, Wind Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

66.5

1 7

6.1.2 Grain Size

Not Applicable

Fine Grained

6.1.3 Fracture

Conchoidal

Flat

6.1.4 Streak

White to Grey

White

6.1.5 Porosity

Less Porous

6.1.6 Luster

Not Available

Vitreous to Metallic

6.1.7 Compressive Strength

37.50 N/mm²35.00 N/mm²

0.15 450

6.1.8 Cleavage

Not Available

Imperfect

6.1.9 Toughness

2.3

2.7

6.1.10 Specific Gravity

2.8-32.4-2.9

0 8.4

6.1.11 Transparency

Opaque

6.1.12 Density

2.9-3.1 g/cm³2.5-3 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.84 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

India, Russia

Japan

7.1.2 Africa

South Africa

Rwanda, Tanzania

7.1.3 Europe

Iceland

Not Yet Found

7.1.4 Others

Not Yet Found

Hawaii Islands

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

7.2.2 South America

Brazil

Colombia

7.3 Deposits in Oceania Continent

7.3.1 Australia

Not Yet Found

All about Variolite and Nephelinite Properties

Know all about Variolite and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite and Nephelinite belong to Igneous Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Nephelinite is Aphanitic. Variolite appears Dull and Soft and Nephelinite appears Skeletal. The luster of Variolite is not available while that of Nephelinite is vitreous to metallic. Variolite is available in black, brown, light to dark grey colors whereas Nephelinite is available in black, brown, colourless, green, grey, white colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).