Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
Discoverer
Unknown
Unknown
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From German Tachylite, from tachy- + Greek lutos soluble, melting
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Banded, Rough
Vitreous
Color
Black, Brown, Green, Grey, Red, White
Black, Dark Brown
Durability
Durable
Durable
Appearance
Glassy or Pearly
Glassy
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Cutting Tool, Knives, Landscaping, Scrapers
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Artifacts
Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Cemetery Markers, Creating Artwork
Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Not Available
Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Available in Lots of Colors and Patterns, Clasts are smooth to touch, NA
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Not Yet Used
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.
Tachylite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Quartz, Silicon
Feldspar, Olivine
Compound Content
Silicon Dioxide
Fe, Mg
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Medium to Fine Coarse Grained
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Porosity
Highly Porous
Less Porous
Luster
Waxy and Dull
Resinous
Cleavage
Non-Existent
Not Available
Toughness
1.5
Not Available
Specific Gravity
2.5-2.8
2.4
Transparency
Translucent to Opaque
Opaque
Density
2.7 g/cm3
3.058 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Cambodia, Russia, South Korea
Africa
Kenya, Morocco, South Africa, Tanzania
East Africa
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
England, Germany, Hungary, Iceland, Scotland, Sweden
Others
Greenland, Mid-Atlantic Ridge
Hawaii Islands
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Bolivia, Brazil
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
Victoria
All about Chert and Tachylite Properties
Know all about Chert and Tachylite properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Tachylite belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Tachylite is Vitreous. Chert appears Glassy or Pearly and Tachylite appears Glassy. The luster of Chert is waxy and dull while that of Tachylite is resinous. Chert is available in black, brown, green, grey, red, white colors whereas Tachylite is available in black, dark brown 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 Tachylite are cemetery markers, creating artwork.