Definition
Anorthosite is a granular igneous rock composed largely of labradorite or plagioclase
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
History
Origin
-
Webster, North Carolina
Discoverer
Unknown
Unknown
Etymology
From French anorthose plagioclase + -ite1
From the town of Webster located in North Carolina
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Foliated, Glassy
Clastic, Granular, Phaneritic, Porphyritic
Color
Black, Bluish - Grey, Brown, Green, Grey, Light Greenish Grey, Pink, White
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Layered, Banded, Veined and Shiny
Layered, Banded, Veined and Shiny
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
-
-
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts
Other Uses
Commercial Uses
Creating Artwork, Curling
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Proterozoic Anorthosite and Archean Anorthosite
Ultramafic rock
Features
Generally rough to touch, Is one of the oldest rock
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Anorthosite is a phaneritic, intrusive igneous rock which is characterized by a predominance of plagioclase feldspar which is almost 90–100%, and a minimal mafic component.
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Composition
Mineral Content
Amphibole, Clinopyroxene, Ilmenite, Magnetite, Olivine, Orthopyroxene
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Compound Content
Ca, CaO, Chromium(III) Oxide, MgO, Sulfur Trioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Impact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
5-67
1
7
👆🏻
Grain Size
Coarse Grained
Coarse Grained
Fracture
Irregular
Uneven
Streak
White
White, Greenish White or Grey
Porosity
Less Porous
Less Porous
Luster
Pearly to Subvitreous
Dull to Vitreous to Submetallic
Compressive Strength
180.00 N/mm295.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
-
Specific Gravity
2.62-2.823.2-3.5
0
8.4
👆🏻
Transparency
Translucent
Opaque
Density
2.7-4 g/cm33.1-3.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K0.79 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
-
India, Russia
Africa
-
South Africa
Europe
Bulgaria, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Malta, Poland, Portugal, Romania, Slovenia, Spain, Sweden, The Czech Republic
Germany, Greece, Italy, Scotland, Turkey
Others
-
Greenland
Deposits in Western Continents
North America
Canada
Canada, USA
South America
Bolivia, Colombia
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Central Australia, South Australia, Western Australia
New Zealand, Queensland