Chert and Andesite
Definition
Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava
History
Origin
Unknown
North America
Discoverer
Unknown
Unknown
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From Andes mountains, where it is found in abundance
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Banded, Rough
Aphanitic to Porphyritic
Color
Black, Brown, Green, Grey, Red, White
Bluish - Grey, Grey, Pink, Yellow
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
Yes
Stain Resistant
Yes
Yes
Wind Resistant
No
No
Acid Resistant
Yes
Yes
Appearance
Glassy or Pearly
Dull and Soft
Uses
Architecture
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Office Buildings, Roof Tiles
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Cobblestones, Construction Aggregate, for Road Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Commemorative Tablets, Creating Artwork
Types
Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Icelandite
Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Generally rough to touch, High silica content, Is one of the oldest rock
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Middle of the Earth in Ecuador
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Not Yet Used
Used
Fossils
Present
Absent
Formation
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.
Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.
Composition
Mineral Content
Quartz, Silicon
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon
Compound Content
Silicon Dioxide
Silicon Dioxide
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
No
Yes
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Properties
Physical Properties
Hardness
6.5-7
7
Grain Size
Very fine-grained
Very fine-grained
Fracture
Uneven, Splintery or Conchoidal
Uneven
Streak
White
White
Porosity
Highly Porous
Less Porous
Luster
Waxy and Dull
Vitreous
Compressive Strength
450.00 N/mm2
1
225.00 N/mm2
7
Cleavage
Non-Existent
Not Available
Toughness
1.5
1.1
Specific Gravity
2.5-2.8
2.5-2.8
Transparency
Translucent to Opaque
Opaque
Density
2.7 g/cm3
2.11-2.36 g/cm3
Thermal Properties
Specific Heat Capacity
0.74 kJ/Kg K
19
2.39 kJ/Kg K
2
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
India, Indonesia, Japan, Nepal, South Korea
Africa
Kenya, Morocco, South Africa, Tanzania
Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom
Others
Greenland, Mid-Atlantic Ridge
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Mexico, USA
South America
Bolivia, Brazil
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
New South Wales, New Zealand, Western Australia
All about Chert and Andesite Properties
Know all about Chert and Andesite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Andesite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Andesite is Aphanitic to Porphyritic. Chert appears Glassy or Pearly and Andesite appears Dull and Soft. The luster of Chert is waxy and dull while that of Andesite is vitreous. Chert is available in black, brown, green, grey, red, white colors whereas Andesite is available in bluish - grey, grey, pink, yellow colors. The commercial uses of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms and that of Andesite are commemorative tablets, creating artwork.
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