Definition
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Discoverer
Unknown
Alexandre Brongniart and René Just Haüy
Etymology
From a Latin word tophous then in Italian tufo and finally tuff
From Greek trakhus rough’ or trakhutēs roughness
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, Opaque Rock
Texture
Clastic, Pyroclastic
Aphanitic to Porphyritic
Color
Brown, Grey, Yellow
Black, Brown, Dark Greenish - Grey, Green, Grey, Light to Dark Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull, Vesicular and Foilated
Banded
Interior Uses
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Decorative Aggregates, Flooring, 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, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork
Cemetery Markers, Creating Artwork
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
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
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.
Trachyte is an igneous volcanic rock with an aphanitic to porphyritic texture. It is the volcanic equivalent of syenite rock and forms as a result of magmatic differentiation.
Mineral Content
Calcite, Chlorite
Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz
Compound Content
Hydrogen Sulfide, Sulfur Dioxide
Potassium Oxide, Sodium Oxide, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Cataclastic Metamorphism, Contact 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, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Uneven
Not Available
Porosity
Highly Porous
Less Porous
Luster
Vitreous to Dull
Metallic
Cleavage
Not Available
Not Available
Toughness
Not Available
Not Available
Specific Gravity
2.73
2.7
Transparency
Opaque
Opaque
Density
1-1.8 g/cm3
2.43-2.45 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact 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
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
Bulgaria, England, Germany, Norway, Romania, Switzerland
Others
Antarctica, Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, Costa Rica, Panama, USA
USA
South America
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
Brazil, Chile
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New Zealand, Queensland, South Australia, Western Australia