Definition
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster
History
Origin
Webster, North Carolina
Pennsylvania, U.S.
Discoverer
Unknown
Unknown
Etymology
From the town of Webster located in North Carolina
From Greek anthrakites, from anthrax, anthrak meaning coal
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Plutonic
-
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Granular, Phaneritic, Porphyritic
Amorphous, Glassy
Color
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Layered, Banded, Veined and Shiny
Veined or Pebbled
Architecture
Interior Uses
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
-
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
-
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Medical Industry
-
In Chemical and Pharmaceutical Industry, Manufacture of Aspirins
Antiquity Uses
Artifacts
-
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Types
Ultramafic rock
Semi-anthracite and Meta-anthracite
Features
Generally rough to touch, Is one of the oldest rock
Helps in production of Heat and Electricity, Used as fossil fuel
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Anthracite forms from the accumulation of plant debris in a swamp environment. When plant debris dies and falls into the swamp, the standing water of the swamp protects it from decay.
Composition
Mineral Content
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Calcite, Clay, Clay Minerals
Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Impact Metamorphism
Burial Metamorphism, Contact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
-
Physical Properties
Hardness
71-1.5
1
7
👆🏻
Grain Size
Coarse Grained
Medium to Fine Coarse Grained
Fracture
Uneven
Conchoidal
Streak
White, Greenish White or Grey
Black
Porosity
Less Porous
Less Porous
Luster
Dull to Vitreous to Submetallic
Shiny
Compressive Strength
95.00 N/mm2-
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
-
Specific Gravity
3.2-3.51.1-1.4
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
3.1-3.6 g/cm31.25-2.5 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.79 kJ/Kg K1.32 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Water Resistant
Deposits in Eastern Continents
Asia
India, Russia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
South Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
Germany, Greece, Italy, Scotland, Turkey
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Others
Greenland
-
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil, Colombia, Venezuela
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, Queensland
New South Wales, Queensland, Victoria