1 Definition
1.1 Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
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 a Latin word tophous then in Italian tufo and finally tuff
1.4 Class
Sedimentary Rocks
Igneous Rocks
1.4.1 Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness 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
Clastic, Pyroclastic
2.2 Color
Black, Brown, Green, Grey, Red, White
Brown, Grey, Yellow
2.3 Maintenance
2.4 Durability
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, Vesicular and Foilated
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Entryways, Flooring, Homes, 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, Office Buildings, Paving Stone
3.1.3 Other Architectural Uses
3.2 Industry
3.2.1 Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Building houses or walls, Construction Aggregate
3.2.2 Medical Industry
Not Yet Used
Not Yet Used
3.3 Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
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
4 Types
4.1 Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
4.2 Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Always found as volcanic pipes over deep continental crust
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Data Not Available
Easter Island in the Polynesian Triangle, Pacific Ocean
4.3.3 Sculpture
4.3.4 Famous Sculptures
Not Applicable
Data Not Available
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
4.4 Fossils
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.
Tuff is formed when large masses of ash and sand which are mixed with hot gases are ejected by a volcano and avalanche rapidly down its slopes.
5.2 Composition
5.2.1 Mineral Content
Quartz, Silicon
Calcite, Chlorite
5.2.2 Compound Content
Silicon Dioxide
Hydrogen Sulfide, Sulfur 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, Mechanical Weathering
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
6 Properties
6.1 Physical Properties
6.1.1 Hardness
6.1.2 Grain Size
Very fine-grained
Fine Grained
6.1.3 Fracture
Uneven, Splintery or Conchoidal
Uneven
6.1.4 Streak
6.1.5 Porosity
Highly Porous
Highly Porous
6.1.6 Luster
Waxy and Dull
Vitreous to Dull
6.1.7 Compressive Strength
450.00 N/mm2243.80 N/mm2
0.15
450
6.1.8 Cleavage
Non-Existent
Not Available
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
Translucent to Opaque
Opaque
6.1.12 Density
2.7 g/cm31-1.8 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
0.74 kJ/Kg K0.20 kJ/Kg K
0.14
3.2
6.2.2 Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure 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
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
7.1.2 Africa
Kenya, Morocco, South Africa, Tanzania
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
7.1.3 Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
7.1.4 Others
Greenland, Mid-Atlantic Ridge
Antarctica, Hawaii Islands
7.2 Deposits in Western Continents
7.2.1 North America
Canada, Mexico, USA
Canada, Costa Rica, Panama, USA
7.2.2 South America
Bolivia, Brazil
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
7.3 Deposits in Oceania Continent
7.3.1 Australia
New South Wales, Queensland, South Australia, Western Australia
Central Australia, Western Australia