Definition
Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster
Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance
Origin
Pennsylvania, U.S.
France
Discoverer
Unknown
Unknown
Etymology
From Greek anthrakites, from anthrax, anthrak meaning coal
From Latin varius, speckled, variegated
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Opaque Rock
Texture
Amorphous, Glassy
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Appearance
Veined or Pebbled
Dull and Soft
Interior Uses
-
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
-
Garden Decoration, Office Buildings
Other Architectural Uses
-
Curbing
Construction Industry
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
In Chemical and Pharmaceutical Industry, Manufacture of Aspirins
-
Antiquity Uses
-
Artifacts, Monuments, Sculpture
Commercial Uses
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Cemetery Markers, Creating Artwork
Types
Semi-anthracite and Meta-anthracite
Metamorphic rock
Features
Helps in production of Heat and Electricity, Used as fossil fuel
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Formation
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.
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
Mineral Content
Calcite, Clay, Clay Minerals
Olivine, Plagioclase, Pyroxene
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Grain Size
Medium to Fine Coarse Grained
-
Fracture
Conchoidal
Conchoidal
Streak
Black
White to Grey
Porosity
Less Porous
Less Porous
Specific Gravity
1.1-1.4
2.8-3
Transparency
Opaque
Opaque
Density
1.25-2.5 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant, Water Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
India, Russia
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
South Africa
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Iceland
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Brazil, Chile, Colombia, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New South Wales, Queensland, Victoria
-
All about Anthracite and Variolite Properties
Know all about Anthracite and Variolite properties here. All properties of rocks are important as they define the type of rock and its application. Anthracite belongs to Metamorphic Rocks while Variolite belongs to Igneous Rocks.Texture of Anthracite is Amorphous, Glassy whereas that of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular. Anthracite appears Veined or Pebbled and Variolite appears Dull and Soft. The luster of Anthracite is shiny while that of Variolite is . Anthracite and Variolite are available in black, brown, dark brown, grey, light to dark grey colors. The commercial uses of Anthracite are alumina refineries, electricity generation, liquid fuel, manufacture of soap, solvents, dyes, plastics and fibres, paper industry and that of Variolite are cemetery markers, creating artwork.