Definition
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Origin
Italy
Adak, Aleutian Islands
Discoverer
Unknown
Defant and Drummond
Etymology
From a Latin word tophous then in Italian tufo and finally tuff
From Adak, Aleutian Islands
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Pyroclastic
Porphyritic
Color
Brown, Grey, Yellow
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull, Vesicular and Foilated
Dull and Soft
Interior Uses
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Curbing
Whetstones
Construction Industry
Building houses or walls, Construction Aggregate
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork
Commemorative Tablets, Pottery, Used in aquariums
Types
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
Not Available
Features
Always found as volcanic pipes over deep continental crust
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Archaeological Significance
Famous Monuments
Easter Island in the Polynesian Triangle, Pacific Ocean
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Formation
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.
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
Mineral Content
Calcite, Chlorite
Olivine, Plagioclase, Pyroxene
Compound Content
Hydrogen Sulfide, Sulfur Dioxide
Aluminium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Grain Size
Fine Grained
Fine to Medium Grained
Fracture
Uneven
Conchoidal
Streak
White
Bluish Black
Porosity
Highly Porous
Less Porous
Luster
Vitreous to Dull
Grainy, Pearly and Vitreous
Compressive Strength
Not Available
Cleavage
Not Available
Not Available
Toughness
Not Available
Not Available
Specific Gravity
2.73
Not Available
Transparency
Opaque
Opaque
Density
1-1.8 g/cm3
Not Available
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
India, Russia
Africa
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
Ethiopia, Somalia, South Africa
Europe
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
Iceland
Others
Antarctica, Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, Costa Rica, Panama, USA
Canada, USA
South America
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
Brazil
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Not Yet Found