Chert

Gneiss

Chert and Gneiss

Chert

Gneiss

Add ⊕

1 Definition

1.1 Definition

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

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

1.2 History

1.2.1 Origin

Unknown

1.2.2 Discoverer

Unknown

1.3 Etymology

From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

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

1.4 Class

Sedimentary Rocks

Metamorphic Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Not Applicable

1.6 Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Banded, Rough

Banded, Foliated, Platy

2.2 Color

Black, Brown, Green, Grey, Red, White

Black, Brown, Pink, Red, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Glassy or Pearly

Foliated

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Homes

Countertops, Decorative Aggregates, Flooring, Interior Decoration

3.1.2 Exterior Uses

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

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

As Dimension Stone

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

4 Types

4.1 Types

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

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

4.2 Features

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Generally rough to touch, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

Konark Sun Temple in India, Washington Monument, US

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Not Used

4.3.6 Petroglyphs

Not Used

4.3.7 Figurines

Not Yet Used

4.4 Fossils

Present

Absent

5 Formation

5.1 Formation

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

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.

5.2 Composition

5.2.1 Mineral Content

Quartz, Silicon

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

5.2.2 Compound Content

Silicon Dioxide

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Not Applicable

Impact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Not Applicable

Biological Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.5-77

1 7

6.1.2 Grain Size

Very fine-grained

Medium to Coarse Grained

6.1.3 Fracture

Uneven, Splintery or Conchoidal

Irregular

6.1.4 Streak

White

6.1.5 Porosity

Highly Porous

Very Less Porous

6.1.6 Luster

Waxy and Dull

Dull

6.1.7 Compressive Strength

450.00 N/mm²125.00 N/mm²

0.15 450

6.1.8 Cleavage

Non-Existent

Poor

6.1.9 Toughness

1.5

1.2

6.1.10 Specific Gravity

2.5-2.82.5-2.7

0 8.4

6.1.11 Transparency

Translucent to Opaque

6.1.12 Density

2.7 g/cm³2.6-2.9 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.74 kJ/Kg KNA

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

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

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

7.1.2 Africa

Kenya, Morocco, South Africa, Tanzania

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

7.1.3 Europe

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

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

7.1.4 Others

Greenland, Mid-Atlantic Ridge

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

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

7.2.2 South America

Bolivia, Brazil

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, Queensland, South Australia, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Chert and Gneiss Properties

Know all about Chert and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Chert is Banded, Rough whereas that of Gneiss is Banded, Foliated, Platy. Chert appears Glassy or Pearly and Gneiss appears Foliated. The luster of Chert is waxy and dull while that of Gneiss is dull. Chert is available in black, brown, green, grey, red, white colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.