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
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
Discoverer
Unknown
Unknown
Etymology
From Latin varius, speckled, variegated
From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Clastic, Splintery
Color
Black, Brown, Light to Dark Grey
Black, Brown, Buff, Green, Grey, Red, Yellow
Durability
Durable
Durable
Appearance
Dull and Soft
Muddy
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Pottery
Types
Not Available
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Jantar Mantar in India
Famous Sculptures
Data Not Available
Data Not Available
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.
Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.
Mineral Content
Olivine, Plagioclase, Pyroxene
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, Fe, Mg, Silicon Dioxide, Sodium
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Not Applicable
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Not Applicable
Very fine-grained
Fracture
Conchoidal
Not Available
Streak
White to Grey
White
Porosity
Less Porous
Highly Porous
Luster
Not Available
Dull
Cleavage
Not Available
Slaty
Specific Gravity
2.8-3
2.2-2.8
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
2.4-2.8 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
India, Russia
Bangladesh, China, India, Russia
Africa
South Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
Iceland
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New South Wales, New Zealand, Queensland, Victoria, Western Australia
All about Variolite and Shale Properties
Know all about Variolite and Shale properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Shale belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Shale is Clastic, Splintery. Variolite appears Dull and Soft and Shale appears Muddy. The luster of Variolite is not available while that of Shale is dull. Variolite is available in black, brown, light to dark grey colors whereas Shale is available in black, brown, buff, green, grey, red, yellow colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Shale are creating artwork, pottery.