Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Oolite is a sedimentary rock formed from ooids, spherical grains which are composed of concentric layers of calcite
History
Origin
-
-
Discoverer
Unknown
William Smith
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From oo- + -lite, after German Oolit. A rock consisting of fine grains of carbonate of lime
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Banded, Rough
Clastic or Non-Clastic
Color
Black, Brown, Green, Grey, Red, White
Black, Blue, Brown, Cream, Green, Grey, Pink, Red, Silver, White, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Glassy or Pearly
Rounded and Rough
Architecture
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Flooring, 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
-
Industry
Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Cement Manufacture, Cobblestones, Landscaping
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments
Artifacts
Other Uses
Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Creating Artwork, Jewelry, Used in aquariums
Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Pisolitic Oolite and Oncolitic Oolite
Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Available in lots of colors, Generally rough to touch, Very fine grained rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Present
Present
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.
Oolites form when layers of calcite are deposited around a sand grain or fossil piece and are rolled around in calm water, which makes them round.
Composition
Mineral Content
Quartz, Silicon
Calcite, Chert, Clay, Dolomite, Quartz, Sand, Silt
Compound Content
Silicon Dioxide
Aluminium Oxide, Ca, NaCl, CaO, Iron(III) Oxide, FeO, MgO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
-
Weathering
✔
✘
✔
✘
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion
Physical Properties
Hardness
6.5-73-4
1
7
👆🏻
Grain Size
Very fine-grained
Fine Grained
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Streak
White
White
Porosity
Highly Porous
Less Porous
Luster
Waxy and Dull
Pearly to Shiny
Compressive Strength
450.00 N/mm240.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
1.5
1
Specific Gravity
2.5-2.8-9999
0
8.4
👆🏻
Transparency
Translucent to Opaque
Opaque
Density
2.7 g/cm3-9999 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.74 kJ/Kg K0.65 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Kenya, Morocco, South Africa, Tanzania
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
United Kingdom
Others
Greenland, Mid-Atlantic Ridge
-
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Bolivia, Brazil
Colombia
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula