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
1.2.2 Discoverer
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
Durable Rock, Hard Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
2 Texture
2.1 Texture
Banded, Rough
Porphyritic
1.2 Color
Black, Brown, Green, Grey, Red, White
Black, Brown, Colourless, Green, Grey, Red, Rust, White
1.3 Maintenance
1.5 Durability
1.5.2 Water Resistant
1.6.1 Scratch Resistant
1.7.1 Stain Resistant
1.7.3 Wind Resistant
1.8.2 Acid Resistant
1.10 Appearance
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Interior Decoration
3.2.1 Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Garden Decoration, Paving Stone
3.3.1 Other Architectural Uses
3.5 Industry
3.5.1 Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Construction Aggregate
3.5.2 Medical Industry
Not Yet Used
Not Yet Used
3.6 Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
3.7 Other Uses
3.7.1 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
4.3.3 Famous Monuments
Data Not Available
Data Not Available
4.4.1 Sculpture
5.1.1 Famous Sculptures
Not Applicable
Data Not Available
5.1.3 Pictographs
5.1.5 Petroglyphs
5.2.2 Figurines
5.3 Fossils
6 Formation
6.1 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.
6.3 Composition
6.3.1 Mineral Content
Quartz, Silicon
Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica
7.1.1 Compound Content
Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
7.3 Transformation
7.3.1 Metamorphism
7.4.2 Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
7.4.3 Weathering
7.4.5 Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Not Registered
7.4.7 Erosion
7.4.9 Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
8 Properties
8.1 Physical Properties
8.1.1 Hardness
10.1.2 Grain Size
Very fine-grained
Fine Grained
10.1.3 Fracture
Uneven, Splintery or Conchoidal
Irregular
10.1.4 Streak
10.1.5 Porosity
Highly Porous
Less Porous
10.1.6 Luster
10.1.7 Compressive Strength
10.1.14 Cleavage
10.1.15 Toughness
10.1.16 Specific Gravity
10.1.20 Transparency
Translucent to Opaque
Translucent to Opaque
10.1.21 Density
2.7 g/cm32.5-2.52 g/cm3
0
1400
10.2 Thermal Properties
10.2.1 Specific Heat Capacity
10.3.2 Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
11 Reserves
11.1 Deposits in Eastern Continents
11.1.1 Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam
11.1.2 Africa
Kenya, Morocco, South Africa, Tanzania
Egypt, Ethiopia, Ghana, South Africa
11.1.3 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
11.1.4 Others
Greenland, Mid-Atlantic Ridge
Greenland
11.2 Deposits in Western Continents
11.2.1 North America
Canada, Mexico, USA
Canada, Cuba, Jamaica, USA
11.2.2 South America
Bolivia, Brazil
Bolivia, Brazil, Colombia, Ecuador, Paraguay
11.3 Deposits in Oceania Continent
11.3.1 Australia
New South Wales, Queensland, South Australia, Western Australia
New South Wales, New Zealand, Western Australia