Variolite and Slate
Definition
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
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
History
Origin
France
England
Discoverer
Unknown
Unknown
Etymology
From Latin varius, speckled, variegated
From Old French esclate, from esclat (French éclat)
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Foliated
Color
Black, Brown, Light to Dark Grey
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
No
Yes
Wind Resistant
No
No
Acid Resistant
Yes
No
Appearance
Dull and Soft
Dull
Uses
Architecture
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
As Dimension Stone
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
Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates
Types
Types
Not Available
Not Available
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Easily splits into thin plates, Surfaces are often shiny, 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
Used
Petroglyphs
Used
Used
Figurines
Used
Used
Fossils
Absent
Absent
Formation
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.
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Composition
Mineral Content
Olivine, Plagioclase, Pyroxene
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
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, Titanium Dioxide
Transformation
Metamorphism
Yes
Yes
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
No
Yes
Types of Erosion
Not Applicable
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
6
3-4
Grain Size
Not Applicable
Very fine-grained
Fracture
Conchoidal
Splintery
Streak
White to Grey
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Not Available
Dull
Compressive Strength
37.50 N/mm2
27
30.00 N/mm2
30
Cleavage
Not Available
Slaty
Toughness
2.3
1.2
Specific Gravity
2.8-3
2.65-2.8
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
2.6-2.8 g/cm3
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K
15
0.76 kJ/Kg K
17
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
India, Russia
China, India, Turkey
Africa
South Africa
Not Yet Found
Europe
Iceland
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Others
Not Yet Found
Arctic
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
Brazil
Deposits in Oceania Continent
Australia
Not Yet Found
Not Yet Found
All about Variolite and Slate Properties
Know all about Variolite and Slate properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Slate belongs to Metamorphic Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Slate is Foliated. Variolite appears Dull and Soft and Slate appears Dull. The luster of Variolite is not available while that of Slate is dull. Variolite is available in black, brown, light to dark grey colors whereas Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates.
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