Tephrite

Gossan

Tephrite and Gossan

Tephrite

Gossan

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Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

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

History

Origin

Germany

Indonesia

Discoverer

Van Tooren

Cornish Gossen

Etymology

From Greek tephra, ashes from Indo-European base, to burn

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

Volcanic

Other Categories

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

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

Vesicular

Dull and Banded

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Landscaping

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

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts

Other Uses

Commercial Uses

Production of Lime, Soil Conditioner

Cemetery Markers, Commemorative Tablets, Gemstone

Types

Igneous rock

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

Tephrite 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

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

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

Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

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

Chemical Erosion, Sea Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.54-5

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fine to Medium Grained

Fracture

Uneven

Conchoidal

Streak

Bluish Black

White to Grey

Porosity

Very Less Porous

Highly Porous

Luster

Subvitreous to Dull

Metallic

Compressive Strength

90.00 N/mm²-

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Toughness

2.4

Specific Gravity

2.862.0

0 8.4

👆🏻

Transparency

Opaque

Density

2.8-2.9 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.24 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Africa

Namibia, Uganda

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

Europe

Germany, Hungary, Italy, Portugal, Spain

Albania, France, Germany, Great Britain, United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada, USA

South America

Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

New South Wales, South Australia, Western Australia

All about Tephrite and Gossan Properties

Know all about Tephrite and Gossan properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Gossan belongs to Metamorphic Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Gossan is Rough, Sandy. Tephrite appears Vesicular and Gossan appears Dull and Banded. The luster of Tephrite is subvitreous to dull while that of Gossan is metallic. Tephrite 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 Tephrite are production of lime, soil conditioner and that of Gossan are cemetery markers, commemorative tablets, gemstone.