Gneiss

Taconite

Gneiss and Taconite

Gneiss

Taconite

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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

Taconite is a low-grade iron ore which belongs to sedimentary rock and containing about 27% iron and 51% silica

History

Origin

Western Australia, Minnesota

Discoverer

Unknown

Newton Horace Winchell

Etymology

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

From the name of Taconic Mountains in New England

Class

Metamorphic Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Other Categories

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Banded, Foliated, Platy

Banded, Trellis

Color

Black, Brown, Pink, Red, White

Red, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Foliated

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Flooring, Interior Decoration

Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

As Dimension Stone, Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

As a touchstone, Cemetery Markers, Creating Artwork

Types

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

Iron formation

Features

Generally rough to touch, Is one of the oldest rock

Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Konark Sun Temple in India, Washington Monument, US

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

Taconite is a type of sedimentary rock formed when a river carries or transports pieces of broken rock as it flows. When the river reaches a lake or sea, its load of transported rocks settles or deposits at the bottom of sea or lake.

Composition

Mineral Content

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

Hematite, Magnetite, Quartz

Compound Content

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

Fe, Iron(III) Oxide, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Impact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

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

Properties

Physical Properties

Hardness

75.5-6

1 7

👆🏻

Grain Size

Medium to Coarse Grained

Large and Coarse Grained

Fracture

Irregular

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Dull

Earthy

Compressive Strength

125.00 N/mm²190.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.2

1.5

Specific Gravity

2.5-2.75-5.3

0 8.4

👆🏻

Transparency

Translucent to Opaque

Density

2.6-2.9 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.70 kJ/Kg K3.20 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

China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

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

Kenya, Morocco, South Africa, 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

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

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

Canada, Mexico, USA

South America

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

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria

New South Wales, Queensland, South Australia, Western Australia

All about Gneiss and Taconite Properties

Know all about Gneiss and Taconite properties here. All properties of rocks are important as they define the type of rock and its application. Gneiss belongs to Metamorphic Rocks while Taconite belongs to Sedimentary Rocks.Texture of Gneiss is Banded, Foliated, Platy whereas that of Taconite is Banded, Trellis. Gneiss appears Foliated and Taconite appears Layered, Banded, Veined and Shiny. The luster of Gneiss is dull while that of Taconite is earthy. Gneiss is available in black, brown, pink, red, white colors whereas Taconite is available in red, reddish brown colors. The commercial uses of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums and that of Taconite are as a touchstone, cemetery markers, creating artwork.