Definition
Siltstone can be defined as a fine-grained sedimentary rock which mainly consists of consolidated silt
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
Discoverer
Unknown
Unknown
Etymology
From English word silt and stone and from Proto-Indo-European root sal and stainaz
From a Latin word tophous then in Italian tufo and finally tuff
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
Clastic
Clastic, Pyroclastic
Color
Brown, Red, Reddish Brown
Brown, Grey, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough
Dull, Vesicular and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
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
Building houses or walls, Construction Aggregate
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Raw material for the manufacture of mortar, Soil Conditioner
Creating Artwork
Types
Siltstone
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
Features
Available in Lots of Colors and Patterns, Easily splits into thin plates, Generally rough to touch, High silica content, Very fine grained rock
Always found as volcanic pipes over deep continental crust
Archaeological Significance
Famous Monuments
-
Easter Island in the Polynesian Triangle, Pacific Ocean
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.
Tuff is formed when large masses of ash and sand which are mixed with hot gases are ejected by a volcano and avalanche rapidly down its slopes.
Mineral Content
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz, Sand, Silica, Silt
Calcite, Chlorite
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Hydrogen Sulfide, Sulfur Dioxide
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Uneven
Porosity
Highly Porous
Highly Porous
Luster
Dull
Vitreous to Dull
Specific Gravity
2.54-2.73
2.73
Transparency
Opaque
Opaque
Density
2.6-2.7 g/cm3
1-1.8 g/cm3
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
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
Africa
Namibia, Nigeria, South Africa
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
Others
Greenland
Antarctica, Hawaii Islands
Deposits in Western Continents
North America
Canada, USA
Canada, Costa Rica, Panama, USA
South America
Brazil
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New South Wales, New Zealand
Central Australia, Western Australia