Nephelinite

Gossan

Nephelinite and Gossan

Nephelinite

Gossan

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Definition

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

Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.

History

Origin

Brazil

Indonesia

Discoverer

Unknown

Cornish Gossen

Etymology

from French néphéline, from Greek nephelē

From Cornish gossen from gos, blood from Old Cornish guit

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Aphanitic

Rough, Sandy

Color

Black, Brown, Green, Grey, White

Brown, Brown- Black, Gold, Green, Rust

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Skeletal

Dull and Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts

Other Uses

Commercial Uses

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

Cemetery Markers, Commemorative Tablets, Gemstone

Types

Peralkaline Nephelinite

Translocated gossan and Leakage gossan

Features

Host Rock for Lead

Clasts are smooth to touch, Easily splits into thin plates

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.

Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.

Composition

Mineral Content

Clinopyroxene, Nepheline, Plagioclase

Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon

Compound Content

Ca, CaO, Carbon, Cl, MgO

Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Sea Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.54-5

1 7

👆🏻

Grain Size

Fine Grained

Fine to Medium Grained

Fracture

Flat

Conchoidal

Streak

White

White to Grey

Porosity

Less Porous

Highly Porous

Luster

Vitreous to Metallic

Metallic

Compressive Strength

35.00 N/mm²-

0.15 450

👆🏻

Cleavage

Toughness

2.7

Specific Gravity

2.4-2.92.0

0 8.4

👆🏻

Transparency

Opaque

Density

2.5-3 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K0.24 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

Japan

China, India, Indonesia, Russia, Singapore, South Korea

Africa

Rwanda, Tanzania

Cape Verde, Ethiopia, Ghana, South Africa, Western Africa

Europe

Albania, France, Germany, Great Britain, United Kingdom

Others

Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

South America

Colombia

Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New South Wales, South Australia, Western Australia

All about Nephelinite and Gossan Properties

Know all about Nephelinite and Gossan properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite belongs to Igneous Rocks while Gossan belongs to Metamorphic Rocks.Texture of Nephelinite is Aphanitic whereas that of Gossan is Rough, Sandy. Nephelinite appears Skeletal and Gossan appears Dull and Banded. The luster of Nephelinite is vitreous to metallic while that of Gossan is metallic. Nephelinite is available in black, brown, green, grey, white colors whereas Gossan is available in brown, brown- black, gold, green, rust colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Gossan are cemetery markers, commemorative tablets, gemstone.