Chert

Comendite

Chert and Comendite

Chert

Comendite

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Definition

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

Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite

History

Origin

Italy

Discoverer

Unknown

Etymology

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

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Medium Grained Rock, Opaque Rock

Texture

Banded, Rough

Porphyritic

Color

Black, Brown, Green, Grey, Red, White

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts

Other Uses

Commercial Uses

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

Cemetery Markers

Types

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

Rhyolite

Features

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

Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock

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.

Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

Quartz, Silicon

Albite, Amphibole, Quartz

Compound Content

Silicon Dioxide

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6.5-76-7

1 7

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Grain Size

Very fine-grained

Medium Grained

Fracture

Uneven, Splintery or Conchoidal

Pervasive

Streak

White

Bluish Black

Porosity

Highly Porous

Luster

Waxy and Dull

Dull

Compressive Strength

450.00 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.5

Specific Gravity

2.5-2.82.38

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China

Africa

Kenya, Morocco, South Africa, Tanzania

East Africa

Europe

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

Italy

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

South America

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

Queensland

All about Chert and Comendite Properties

Know all about Chert and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Comendite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Comendite is Porphyritic. Chert appears Glassy or Pearly and Comendite appears Foliated. The luster of Chert is waxy and dull while that of Comendite is dull. Chert is available in black, brown, green, grey, red, white colors whereas Comendite is available in blue, bluish - grey 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 Comendite are cemetery markers.