Chert

Porphyry

Chert and Porphyry

Chert

Porphyry

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1 Definition

1.1 Definition

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

Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix

1.2 History

1.2.1 Origin

Unknown

Egypt

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 Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites

1.4 Class

Sedimentary Rocks

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Not Applicable

Plutonic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Banded, Rough

Porphyritic

2.2 Color

Black, Brown, Green, Grey, Red, White

Black, Brown, Colourless, Green, Grey, Red, Rust, 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

Dull

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

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

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

Construction Aggregate

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

3.4 Other Uses

3.4.1 Commercial Uses

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

Creating Artwork, Gemstone, Jewelry

4 Types

4.1 Types

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

Rhomb Porphyry

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, Surfaces are often shiny

4.3 Archaeological Significance

4.3.1 Monuments

Used

4.3.2 Famous Monuments

Data Not Available

4.3.3 Sculpture

Not Yet Used

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Not Used

4.3.6 Petroglyphs

Not Used

4.3.7 Figurines

Not Yet Used

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.

Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.

5.2 Composition

5.2.1 Mineral Content

Quartz, Silicon

Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica

5.2.2 Compound Content

Silicon Dioxide

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Not Applicable

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

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Not Applicable

Biological Weathering, Chemical Weathering, Not Registered

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.5-76-7

1 7

6.1.2 Grain Size

Very fine-grained

Fine Grained

6.1.3 Fracture

Uneven, Splintery or Conchoidal

Irregular

6.1.4 Streak

White

6.1.5 Porosity

Highly Porous

Less Porous

6.1.6 Luster

Waxy and Dull

Dull

6.1.7 Compressive Strength

450.00 N/mm²NA

0.15 450

6.1.8 Cleavage

Non-Existent

Imperfect

6.1.9 Toughness

1.5

1.7

6.1.10 Specific Gravity

2.5-2.82.5-4

0 8.4

6.1.11 Transparency

Translucent to Opaque

6.1.12 Density

2.7 g/cm³2.5-2.52 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, Impact 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, Kazakhstan, South Korea, Thailand, Turkey, Vietnam

7.1.2 Africa

Kenya, Morocco, South Africa, Tanzania

Egypt, Ethiopia, Ghana, South Africa

7.1.3 Europe

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

Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland

7.1.4 Others

Greenland, Mid-Atlantic Ridge

Greenland

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Mexico, USA

Canada, Cuba, Jamaica, USA

7.2.2 South America

Bolivia, Brazil

Bolivia, Brazil, Colombia, Ecuador, Paraguay

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, Queensland, South Australia, Western Australia

New South Wales, New Zealand, Western Australia

All about Chert and Porphyry Properties

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