Gneiss

Scoria

Gneiss and Scoria

Gneiss

Scoria

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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

Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities

History

Origin

Discoverer

Unknown

Etymology

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

From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Banded, Foliated, Platy

Vesicular

Color

Black, Brown, Pink, Red, White

Black, Brown, Dark Grey to Black, Red

Maintenance

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Foliated

Glassy and Vesicular

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Flooring, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

Cement Manufacture, Construction Aggregate, for Road Aggregate, In landscaping and drainage works

Medical Industry

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

As a traction material on snow-covered roads, Creating Artwork, High-temperature insulation, In gas barbecue grills

Types

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

Basaltic Scoria and Andesitic Scoria

Features

Generally rough to touch, Is one of the oldest rock

Available in Lots of Colors and Patterns, Generally rough to touch, Surfaces are often shiny

Archaeological Significance

Monuments

Famous Monuments

Konark Sun Temple in India, Washington Monument, US

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.

Scoria forms when magma containing huge amount of dissolved gas flows from a volcano during an eruption.

Composition

Mineral Content

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

Apatite, Biotite, Calcite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz, Silica

Compound Content

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

Ca, NaCl

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Impact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

75-6

1 7

👆🏻

Grain Size

Medium to Coarse Grained

Fine Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

125.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.2

2.1

Specific Gravity

2.5-2.7-9999

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.6-2.9 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.70 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Indonesia, Japan, Russia

Africa

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

Ethiopia, Kenya, Tanzania

Europe

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

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

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

Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA

South America

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

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria

New Zealand, Western Australia

All about Gneiss and Scoria Properties

Know all about Gneiss and Scoria properties here. All properties of rocks are important as they define the type of rock and its application. Gneiss belongs to Metamorphic Rocks while Scoria belongs to Igneous Rocks.Texture of Gneiss is Banded, Foliated, Platy whereas that of Scoria is Vesicular. Gneiss appears Foliated and Scoria appears Glassy and Vesicular. The luster of Gneiss is dull while that of Scoria is subvitreous to dull. Gneiss is available in black, brown, pink, red, white colors whereas Scoria is available in black, brown, dark grey to black, red colors. The commercial uses of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums and that of Scoria are as a traction material on snow-covered roads, creating artwork, high-temperature insulation, in gas barbecue grills.