Chert

Shonkinite

Chert and Shonkinite

Chert

Shonkinite

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Definition

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

Shonkinite is a rare, dark-coloured and intrusive igneous rock which contains augite and orthoclase feldspar as its primary constituents

History

Origin

USA

Discoverer

Unknown

Etymology

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

From the name of Shonkin Sag ranges in the Highwood Mountains of north-central Montana, US

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Other Categories

Fine Grained Rock, Opaque Rock

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

Texture

Banded, Rough

Earthy

Color

Black, Brown, Green, Grey, Red, White

Brown, Buff, Cream, Green, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

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

Cemetery Markers, Creating Artwork

Types

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

Igneous rock

Features

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

Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

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.

Shonkinites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.

Composition

Mineral Content

Quartz, Silicon

Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz

Compound Content

Silicon Dioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.5-75.5-6

1 7

👆🏻

Grain Size

Very fine-grained

Medium to Fine Coarse Grained

Fracture

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Waxy and Dull

Subvitreous to Dull

Compressive Strength

450.00 N/mm²150.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.5

Specific Gravity

2.5-2.82.6-2.7

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³2.6-2.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam

Africa

Kenya, Morocco, South Africa, Tanzania

Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa

Europe

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

Bulgaria, England, Germany, Norway, Romania, Switzerland

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

USA

South America

Bolivia, Brazil

Brazil, Chile

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

New Zealand, Queensland, South Australia, Western Australia

All about Chert and Shonkinite Properties

Know all about Chert and Shonkinite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Shonkinite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Shonkinite is Earthy. Chert appears Glassy or Pearly and Shonkinite appears Banded and Foilated. The luster of Chert is waxy and dull while that of Shonkinite is subvitreous to dull. Chert is available in black, brown, green, grey, red, white colors whereas Shonkinite is available in brown, buff, cream, green, grey, pink, 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 Shonkinite are cemetery markers, creating artwork.