Definition
Siltstone can be defined as a fine-grained sedimentary rock which mainly consists of consolidated silt
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 word silt and stone and from Proto-Indo-European root sal and stainaz
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, Hard Rock
Durable Rock, Hard Rock
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic
Banded, Rough
Color
Brown, Red, Reddish Brown
Black, Brown, Green, Grey, Red, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough
Glassy or Pearly
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments
Commercial Uses
Raw material for the manufacture of mortar, Soil Conditioner
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Types
Not Available
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Features
Available in Lots of Colors and Patterns, Easily splits into thin plates, Generally rough to touch, High silica content, Very fine grained rock
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Used
Not Yet Used
Formation
Siltstone is a type of sedimentary rock which is formed from fine rock particles. As the particles of eroded rock travel along with water, the edges of the rock are worn-out by water into a rounded shape.
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
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz, Sand, Silica, Silt
Quartz, Silicon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Silicon Dioxide
Types of Metamorphism
Not Applicable
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion
Grain Size
Fine Grained
Very fine-grained
Fracture
Conchoidal
Uneven, Splintery or Conchoidal
Porosity
Highly Porous
Highly Porous
Luster
Dull
Waxy and Dull
Compressive Strength
Not Available
Cleavage
Not Available
Non-Existent
Specific Gravity
2.54-2.73
2.5-2.8
Transparency
Opaque
Translucent to Opaque
Density
2.6-2.7 g/cm3
2.7 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Water Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
Namibia, Nigeria, South Africa
Kenya, Morocco, South Africa, Tanzania
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
Greenland
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil
Bolivia, Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
New South Wales, Queensland, South Australia, Western Australia