Nephelinite

Picrite

Nephelinite and Picrite

Nephelinite

Picrite

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Definition

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

Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine

History

Origin

Brazil

Hawaii Islands

Discoverer

Unknown

Etymology

from French néphéline, from Greek nephelē

From Greek pikros bitter + -ite, 19th century

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Aphanitic

Earthy, Rough

Color

Black, Brown, Green, Grey, White

Black, Brown, Green, Grey, Pink, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Skeletal

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Countertops, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

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

As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)

Types

Peralkaline Nephelinite

Oceanite

Features

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Picrite 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

Clinopyroxene, Nepheline, Plagioclase

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

Ca, CaO, Carbon, Cl, MgO

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.56.8

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Flat

Uneven

Streak

White

White, Greenish White or Grey

Porosity

Less Porous

Luster

Vitreous to Metallic

Subvitreous to Dull

Compressive Strength

35.00 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.7

2.1

Specific Gravity

2.4-2.92.75-2.92

0 8.4

👆🏻

Transparency

Opaque

Density

2.5-3 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan

India, Russia

Africa

Rwanda, Tanzania

South Africa

Europe

Iceland

Others

Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

South America

Colombia

Brazil

Deposits in Oceania Continent

Australia

All about Nephelinite and Picrite Properties

Know all about Nephelinite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Picrite belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Picrite is Earthy, Rough. Nephelinite appears Skeletal and Picrite appears Rough and Shiny. The luster of Nephelinite is vitreous to metallic while that of Picrite is subvitreous to dull. Nephelinite is available in black, brown, green, grey, white colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).