Variolite

Nephelinite

Variolite and Nephelinite

Variolite

Nephelinite

Add ⊕

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).

History

Origin

France

Brazil

Discoverer

Unknown

Etymology

From Latin varius, speckled, variegated

from French néphéline, from Greek nephelē

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Plutonic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Aphanitic

Color

Black, Brown, Light to Dark Grey

Black, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Skeletal

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

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

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

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

Types

Metamorphic rock

Peralkaline Nephelinite

Features

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

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Clinopyroxene, Nepheline, Plagioclase

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

66.5

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal

Flat

Streak

White to Grey

White

Porosity

Less Porous

Luster

Vitreous to Metallic

Compressive Strength

37.50 N/mm²35.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.3

2.7

Specific Gravity

2.8-32.4-2.9

0 8.4

👆🏻

Transparency

Opaque

Density

2.9-3.1 g/cm³2.5-3 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Japan

Africa

South Africa

Rwanda, Tanzania

Europe

Iceland

Others

Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Colombia

Deposits in Oceania Continent

Australia

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 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, 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).