Definition
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
Greenschist is a metamorphic rock that is formed under lowest temperatures and pressures and is usually produced by regional metamorphism
Discoverer
Unknown
Unknown
Etymology
From a Latin word tophous then in Italian tufo and finally tuff
From minerals such as chlorite, serpentine, and epidote, and platy minerals such as muscovite and platy serpentine which are green in color
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Pyroclastic
Foliated, Platy
Color
Brown, Grey, Yellow
Dark Greenish - Grey, Green
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull, Vesicular and Foilated
Layered and Shiny
Interior Uses
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Bathrooms, Countertops, Decorative Aggregates, Entryways, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Construction Aggregate
As Dimension Stone, Building houses or walls, Cement Manufacture, Cutting Tool, for Road Aggregate, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Creating Artwork
Blackboards, Manufacture of tools, Writing Slates
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
Easily splits into thin plates, Smooth to touch
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Easter Island in the Polynesian Triangle, Pacific Ocean
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Figurines
Used
Not Yet Used
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.
Greenschist is medium grade metamorphic rock, formed by the metamorphosis of mudstone or shale, or some types of igneous rock, when it is subjected to higher temperatures and pressures.
Mineral Content
Calcite, Chlorite
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Serpentine, Sillimanite, Staurolite, Talc
Compound Content
Hydrogen Sulfide, Sulfur Dioxide
CaO, Carbon Dioxide, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Uneven
Conchoidal
Porosity
Highly Porous
Highly Porous
Luster
Vitreous to Dull
Shiny
Compressive Strength
Not Available
Cleavage
Not Available
Slaty
Toughness
Not Available
1.5
Specific Gravity
2.73
2.5-2.9
Transparency
Opaque
Opaque
Density
1-1.8 g/cm3
2.8-2.9 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Impact Resistant, Pressure Resistant, Water 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
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
Africa
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Europe
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Others
Antarctica, Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, Costa Rica, Panama, USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
Brazil, Colombia, Guyana
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New South Wales, New Zealand, Queensland