Nephelinite

Variolite

Nephelinite and Variolite

Nephelinite

Variolite

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1 Definition

1.1 Definition

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

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

1.2 History

1.2.1 Origin

Brazil

France

1.2.2 Discoverer

Unknown

1.3 Etymology

from French néphéline, from Greek nephelē

From Latin varius, speckled, variegated

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Plutonic

Volcanic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

2 Texture

2.1 Texture

Aphanitic

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

2.2 Color

Black, Brown, Colourless, Green, Grey, White

Black, Brown, Light to Dark Grey

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

Skeletal

Dull and Soft

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Floor Tiles, Flooring, Homes, Hotels, Kitchens

3.1.2 Exterior Uses

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

Garden Decoration, Office Buildings

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

3.4 Other Uses

3.4.1 Commercial Uses

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

Cemetery Markers, Creating Artwork

4 Types

4.1 Types

Peralkaline Nephelinite

Not Available

4.2 Features

Host Rock for Lead

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

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

Not Used

Used

4.3.6 Petroglyphs

Not Used

Used

4.3.7 Figurines

Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

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.

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

5.2 Composition

5.2.1 Mineral Content

Clinopyroxene, Nepheline, Plagioclase

Olivine, Plagioclase, Pyroxene

5.2.2 Compound Content

Ca, CaO, Carbon, Cl, MgO

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional 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

Chemical Erosion, Water Erosion, Wind Erosion

Not Applicable

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.56

1 7

6.1.2 Grain Size

Fine Grained

Not Applicable

6.1.3 Fracture

Flat

Conchoidal

6.1.4 Streak

White

White to Grey

6.1.5 Porosity

Less Porous

6.1.6 Luster

Vitreous to Metallic

Not Available

6.1.7 Compressive Strength

35.00 N/mm²37.50 N/mm²

0.15 450

6.1.8 Cleavage

Imperfect

Not Available

6.1.9 Toughness

2.7

2.3

6.1.10 Specific Gravity

2.4-2.92.8-3

0 8.4

6.1.11 Transparency

Opaque

6.1.12 Density

2.5-3 g/cm³2.9-3.1 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.88 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Japan

India, Russia

7.1.2 Africa

Rwanda, Tanzania

South Africa

7.1.3 Europe

Not Yet Found

Iceland

7.1.4 Others

Hawaii Islands

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

7.2.2 South America

Colombia

Brazil

7.3 Deposits in Oceania Continent

7.3.1 Australia

Not Yet Found

All about Nephelinite and Variolite Properties

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