1 Definition
1.1 Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
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 Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
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
Opaque Rock
2 Texture
2.1 Texture
2.2 Color
Black, Brown, Green, Grey, Red, White
Black, Blue, Brown, Green, Orange, Red, Tan, 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
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
3.1.3 Other Architectural Uses
3.2 Industry
3.2.1 Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
3.2.2 Medical Industry
3.3 Antiquity Uses
Artifacts, Monuments
Artifacts, Jewellery
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, Mirror, Used in aquariums
4 Types
4.1 Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
4.2 Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Blocks negativity, Helps to protect against depression
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Data Not Available
Not Applicable
4.3.3 Sculpture
Not Yet Used
Not Yet Used
4.3.4 Famous Sculptures
Not Applicable
Not Applicable
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
Not Yet Used
Not Yet Used
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.
When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.
5.2 Composition
5.2.1 Mineral Content
Quartz, Silicon
Not Available
5.2.2 Compound Content
Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, 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
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
6 Properties
6.1 Physical Properties
6.1.1 Hardness
6.1.2 Grain Size
Very fine-grained
Not Applicable
6.1.3 Fracture
Uneven, Splintery or Conchoidal
Conchoidal
6.1.4 Streak
6.1.5 Porosity
Highly Porous
Very Less Porous
6.1.6 Luster
6.1.7 Compressive Strength
450.00 N/mm20.15 N/mm2
0.15
450
6.1.8 Cleavage
Non-Existent
Non-Existent
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
Translucent to Opaque
Translucent
6.1.12 Density
2.7 g/cm32.6 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
0.74 kJ/Kg K0.92 kJ/Kg K
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
Afghanistan, Indonesia, Japan, Russia
7.1.2 Africa
Kenya, Morocco, South Africa, Tanzania
Kenya
7.1.3 Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Greece, Hungary, Iceland, Italy, Turkey
7.1.4 Others
Greenland, Mid-Atlantic Ridge
Not Yet Found
7.2 Deposits in Western Continents
7.2.1 North America
Canada, Mexico, USA
Canada, Mexico, USA
7.2.2 South America
Bolivia, Brazil
Argentina, Chile, Ecuador, Peru
7.3 Deposits in Oceania Continent
7.3.1 Australia
New South Wales, Queensland, South Australia, Western Australia
New Zealand