1 Definition
1.1 Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock
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 German which means hornstone
1.4 Class
Sedimentary Rocks
Metamorphic Rocks
1.4.1 Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
1.5 Family
1.5.1 Group
Not Applicable
Not Applicable
1.6 Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
2 Texture
2.1 Texture
Banded, Rough
Granular, Platy
2.2 Color
Black, Brown, Green, Grey, Red, White
Brown, Dark Greenish - Grey, Green, Reddish Brown
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, 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
for Road Aggregate, Roadstone
3.2.2 Medical Industry
Not Yet Used
Not Yet Used
3.3 Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments
3.4 Other Uses
3.4.1 Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Cemetery Markers, Commemorative Tablets, Creating Artwork
4 Types
4.1 Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Biotite hornfels
4.2 Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Smooth to touch
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Data Not Available
Data Not Available
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
5.2 Composition
5.2.1 Mineral Content
Quartz, Silicon
Andalusite
5.2.2 Compound Content
5.3 Transformation
5.3.1 Metamorphism
5.3.2 Types of Metamorphism
Not Applicable
Not Applicable
5.3.3 Weathering
5.3.4 Types of Weathering
Not Applicable
Biological Weathering
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion
Chemical 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
Conchoidal
6.1.4 Streak
6.1.5 Porosity
Highly Porous
Highly Porous
6.1.6 Luster
6.1.7 Compressive Strength
450.00 N/mm25.80 N/mm2
0.15
450
6.1.8 Cleavage
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
Translucent to Opaque
Opaque
6.1.12 Density
2.7 g/cm30.25-0.30 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
0.74 kJ/Kg K0.84 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
7 Reserves
7.1 Deposits in Eastern Continents
7.1.1 Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
7.1.2 Africa
Kenya, Morocco, South Africa, Tanzania
Cameroon, East Africa, Tanzania, Western Africa
7.1.3 Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
United Kingdom
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, USA
7.2.2 South America
Bolivia, Brazil
Bolivia, Brazil, Colombia, Ecuador
7.3 Deposits in Oceania Continent
7.3.1 Australia
New South Wales, Queensland, South Australia, Western Australia
New South Wales, New Zealand, Queensland, Western Australia