Definition
Claystone is a fine-grained, dark gray to pink sedimentary rock which mainly consists of compacted and hardened clay
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Discoverer
Unknown
Unknown
Etymology
From English clay and stone as the rock contains more amount of clay
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic
Banded, Rough
Color
Black, Blue, Brown, Green, Grey, Orange, Red, White, Yellow
Black, Brown, Green, Grey, Red, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Dull
Glassy or Pearly
Interior Uses
Decorative Aggregates, Entryways, Floor Tiles, Homes, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
As Facing Stone, Roof Tiles
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments
Commercial Uses
Pottery
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Types
Claystone
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Features
Available in Lots of Colors and Patterns, Smooth to touch, Very fine grained rock
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Archaeological Significance
Formation
Claystone is generally quite soft, but can be hard and brittle. It forms due to weathering of mudstone.
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.
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Quartz, Silicon
Compound Content
Aluminium Oxide, Ca, NaCl, CaO, Iron(III) Oxide, MgO, Silicon Dioxide
Silicon Dioxide
Types of Metamorphism
-
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Coastal Erosion, Water Erosion
Chemical Erosion
Grain Size
Fine Grained
Very fine-grained
Fracture
-
Uneven, Splintery or Conchoidal
Porosity
Very Less Porous
Highly Porous
Luster
Dull
Waxy and Dull
Specific Gravity
0
2.5-2.8
Transparency
Opaque
Translucent to Opaque
Density
2-2.9 g/cm3
2.7 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Kenya, Morocco, South Africa, Tanzania
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
-
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
Canada, Panama, USA
Canada, Mexico, USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Bolivia, Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New South Wales, Queensland, South Australia, Western Australia