Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Basaltic Trachyandesite is an extrusive igneous rock which is a type of Basalt rock and is formed by the rapid cooling of basaltic lava exposed at or very near the Earth's surface
Discoverer
Unknown
Unknown
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From its mineral and compound content and its relation with Basalt and Andesite rock
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Banded, Rough
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Black, Brown, Green, Grey, Red, White
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Glassy or Pearly
Dull and Soft
Interior Uses
Decorative Aggregates, Homes
Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing, Whetstones
Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments
Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
An Oil and Gas Reservoir, Commemorative Tablets, Creating Artwork
Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
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.
Basaltic Trachandesite is a fine-grained, hard rock that forms when bits of lava shoot out of volcanoes.
Mineral Content
Quartz, Silicon
Olivine, Plagioclase, Pyroxene
Compound Content
Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
-
Contact Metamorphism
Types of Weathering
-
Biological Weathering
Types of Erosion
Chemical Erosion
-
Grain Size
Very fine-grained
Fine Grained
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Streak
White
White to Grey
Porosity
Highly Porous
Less Porous
Specific Gravity
2.5-2.8
2.8-3
Transparency
Translucent to Opaque
Opaque
Density
2.7 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
India, Russia
Africa
Kenya, Morocco, South Africa, Tanzania
South Africa
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Iceland
Others
Greenland, Mid-Atlantic Ridge
-
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Bolivia, Brazil
Brazil
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
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All about Chert and Basaltic Trachyandesite Properties
Know all about Chert and Basaltic Trachyandesite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Basaltic Trachyandesite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Basaltic Trachyandesite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular. Chert appears Glassy or Pearly and Basaltic Trachyandesite appears Dull and Soft. The luster of Chert is waxy and dull while that of Basaltic Trachyandesite is . Chert is available in black, brown, green, grey, red, white colors whereas Basaltic Trachyandesite is available in black, brown, light to dark grey 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 Basaltic Trachyandesite are an oil and gas reservoir, commemorative tablets, creating artwork.