Definition
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
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Discoverer
Unknown
John Peter Salley
Etymology
From Latin varius, speckled, variegated
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Amorphous, Glassy
Color
Black, Brown, Light to Dark Grey
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull and Soft
Veined or Pebbled
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Not Available
Exterior Uses
Garden Decoration, Office Buildings
Not Available
Other Architectural Uses
Curbing
Not Available
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Medical Industry
Not Available
Not Available
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
Cemetery Markers, Creating Artwork
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Types
Not Available
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Helps in production of Heat and Electricity, Used as fossil fuel
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Not Available
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Used
Not Yet Used
Formation
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
Coal forms from the accumulation of plant debris in a swamp environment which is buried by sediments such as mud or sand and then compacted to form coal.
Mineral Content
Olivine, Plagioclase, Pyroxene
Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Types of Erosion
Not Applicable
Not Applicable
Grain Size
Not Applicable
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
Black
Porosity
Less Porous
Less Porous
Luster
Not Available
Dull to Vitreous to Submetallic
Compressive Strength
Not Available
Cleavage
Not Available
Not Available
Toughness
2.3
Not Available
Specific Gravity
2.8-3
1.1-1.4
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
1100-1400 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat 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
Iceland
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Others
Not Available
Not Available
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Not Available
New South Wales, Queensland, Victoria
All about Variolite and Coal Properties
Know all about Variolite and Coal properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Coal belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Coal is Amorphous, Glassy. Variolite appears Dull and Soft and Coal appears Veined or Pebbled. The luster of Variolite is not available while that of Coal is dull to vitreous to submetallic. Variolite is available in black, brown, light to dark grey colors whereas Coal is available in black, brown, dark brown, grey, light to dark grey colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Coal are alumina refineries, electricity generation, liquid fuel, manufacture of soap, solvents, dyes, plastics and fibres, paper industry.