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
  
A ganister is a hard, fine-grained quartzose sandstone or orthoquartzite which is basically used in the manufacture of silica brick typically used to line furnaces and is a type of sedimentary rocks.
  
History
  
  
Origin
France
  
England
  
Discoverer
Unknown
  
Unknown
  
Etymology
From Latin varius, speckled, variegated
  
From gan′is-ter i.e a hard, close-grained siliceous stone, often forming the stratum which underlies a coal-seam
  
Class
Igneous Rocks
  
Sedimentary Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Volcanic
  
Not Applicable
  
Other Categories
Opaque Rock
  
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
  
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
  
Clastic, Granular, Rough
  
Color
Black, Brown, Light to Dark Grey
  
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
Yes
  
No
  
Appearance
Dull and Soft
  
Rough
  
Architecture
  
  
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
  
Decorative Aggregates, Entryways, Flooring, Homes, Interior Decoration
  
Exterior Uses
Garden Decoration, Office Buildings
  
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
  
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Cemetery Markers, Creating Artwork
  
An Oil and Gas Reservoir, In aquifers, Petroleum reservoirs, Soil Conditioner, Source of Magnesia (MgO), Tombstones
  
Types
Not Available
  
Not Available
  
Features
Has High structural resistance against erosion and climate, Very fine grained rock
  
Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Present
  
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.
  
Ganisters are formed by the destruction of easily weathered minerals mainly feldspar, within the surface horizon of soil by soil-forming processes.
  
Composition
  
  
Mineral Content
Olivine, Plagioclase, Pyroxene
  
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
  
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
No
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Not Applicable
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Applicable
  
Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
6
  
6-7
  
Grain Size
Not Applicable
  
Coarse or Fine
  
Fracture
Conchoidal
  
Splintery
  
Streak
White to Grey
  
White
  
Porosity
Less Porous
  
Highly Porous
  
Luster
Not Available
  
Dull
  
Compressive Strength
37.50 N/mm2
  
27
95.00 N/mm2
  
20
Cleavage
Not Available
  
Perfect
  
Toughness
2.3
  
2.6
  
Specific Gravity
2.8-3
  
2.2-2.8
  
Transparency
Opaque
  
Opaque
  
Density
2.9-3.1 g/cm3
  
2.2-2.8 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.84 kJ/Kg K
  
15
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant
  
Deposits in Eastern Continents
  
  
Asia
India, Russia
  
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
  
Africa
South Africa
  
Namibia, Nigeria, South Africa
  
Europe
Iceland
  
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
  
Others
Not Yet Found
  
Greenland
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Brazil
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
Not Yet Found
  
New South Wales, New Zealand
  
All about Variolite and Ganister Properties
Know all about Variolite and Ganister properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Ganister belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Ganister is Clastic, Granular, Rough. Variolite appears Dull and Soft and Ganister appears Rough. The luster of Variolite is not available while that of Ganister is dull. Variolite is available in black, brown, light to dark grey colors whereas Ganister is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Ganister are an oil and gas reservoir, in aquifers, petroleum reservoirs, soil conditioner, source of magnesia (mgo), tombstones.