Definition
Pyroxenite is a dark, greenish, granular intrusive igneous rock consisting mainly of pyroxenes and olivine
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption
Discoverer
Unknown
Unknown
Etymology
From pyro- fire + Greek xenos stranger as the mineral group was new to igneous rocks
From a Latin word tophous then in Italian tufo and finally tuff
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic, Granular, Phaneritic, Porphyritic
Clastic, Pyroclastic
Color
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Brown, Grey, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Layered, Banded, Veined and Shiny
Dull, Vesicular and Foilated
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration, Kitchens
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Building houses or walls, Construction Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Creating Artwork
Types
Clinopyroxenites, Orthopyroxenites and Websterites
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
Features
Generally rough to touch, Host rock for Diamond, Is one of the oldest rock
Always found as volcanic pipes over deep continental crust
Archaeological Significance
Famous Monuments
-
Easter Island in the Polynesian Triangle, Pacific Ocean
Formation
Pyroxenites are ultramafic igneous rocks which are made up of minerals of the pyroxene group, such as augite and diopside, hypersthene, bronzite or enstatite.
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
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Calcite, Chlorite
Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Hydrogen Sulfide, Sulfur Dioxide
Types of Metamorphism
Burial Metamorphism, Impact Metamorphism, Regional 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, Water Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Coarse Grained
Fine Grained
Streak
White, Greenish White or Grey
White
Porosity
Less Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
Vitreous to Dull
Specific Gravity
3.2-3.5
2.73
Transparency
Opaque
Opaque
Density
3.1-3.6 g/cm3
1-1.8 g/cm3
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
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
South Africa
Cameroon, Cape Verde, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Uganda
Europe
Germany, Greece, Italy, Scotland, Turkey
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, Colombia, Venezuela
Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay
Deposits in Oceania Continent
Australia
New Zealand, Queensland
Central Australia, Western Australia