Gneiss

Soapstone

Gneiss and Soapstone

Gneiss

Soapstone

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Definition

Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks

It is a metamorphic magnesium rich rock because it is composed of the mineral talc

History

Origin

USA

Discoverer

Unknown

Etymology

From the Middle High German verb gneist (to spark; so called because the rock glitters)

From 17th century, because of its greasy feel and use like a soap

Class

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Other Categories

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Banded, Foliated, Platy

Polished

Color

Black, Brown, Pink, Red, White

Black, Black to Grey, Green, Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Foliated

Dull, Banded and Foilated

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Flooring, Interior Decoration

Bathrooms, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Taken as a Supplement for Calcium or Magnesium

Antiquity Uses

Artifacts

Artifacts, Jewellery, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)

Types

Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.

Metamorphic rock

Features

Generally rough to touch, Is one of the oldest rock

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Konark Sun Temple in India, Washington Monument, US

Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.

Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.

Composition

Mineral Content

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz

Compound Content

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

CaO, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Impact Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Properties

Physical Properties

Hardness

1 7

👆🏻

Grain Size

Medium to Coarse Grained

Fine Grained

Fracture

Irregular

Conchoidal

Streak

White

Black

Porosity

Very Less Porous

Less Porous

Luster

Dull

Greasy

Compressive Strength

125.00 N/mm²225.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.2

Specific Gravity

2.5-2.72.86

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.6-2.9 g/cm³2.8-2.9 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.70 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Heat Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia

China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand

Africa

Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo

Egypt, Ethiopia, Ghana, South Africa, Western Africa

Europe

Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom

Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom

Others

Deposits in Western Continents

North America

Canada, Costa Rica, Cuba, Mexico, Panama, USA

Canada, USA

South America

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela

Colombia

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria

Central Australia, New Zealand, Queensland

All about Gneiss and Soapstone Properties

Know all about Gneiss and Soapstone properties here. All properties of rocks are important as they define the type of rock and its application. Gneiss and Soapstone belong to Metamorphic Rocks.Texture of Gneiss is Banded, Foliated, Platy whereas that of Soapstone is Polished. Gneiss appears Foliated and Soapstone appears Dull, Banded and Foilated. The luster of Gneiss is dull while that of Soapstone is greasy. Gneiss is available in black, brown, pink, red, white colors whereas Soapstone is available in black, black to grey, green, grey colors. The commercial uses of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums and that of Soapstone are cemetery markers, creating artwork, gemstone, jewelry, manufacture of soap, solvents, dyes, plastics and fibres, production of lime, source of magnesia (mgo).