Variolite and Siltstone
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
Siltstone can be defined as a fine-grained sedimentary rock which mainly consists of consolidated silt
History
Origin
France
Unknown
Discoverer
Unknown
Unknown
Etymology
From Latin varius, speckled, variegated
From English word silt and stone and from Proto-Indo-European root sal and stainaz
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Clastic
Color
Black, Brown, Light to Dark Grey
Brown, Red, Reddish Brown
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
No
No
Wind Resistant
No
Yes
Acid Resistant
Yes
Yes
Appearance
Dull and Soft
Rough
Uses
Architecture
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Building houses or walls, 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, Small Figurines
Other Uses
Commercial Uses
Cemetery Markers, Creating Artwork
Raw material for the manufacture of mortar, Soil Conditioner
Types
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, Easily splits into thin plates, Generally rough to touch, High silica content, Very fine grained rock
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
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
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.
Siltstone is a type of sedimentary rock which is formed from fine rock particles. As the particles of eroded rock travel along with water, the edges of the rock are worn-out by water into a rounded shape.
Composition
Mineral Content
Olivine, Plagioclase, Pyroxene
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz, Sand, Silica, Silt
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, Chemical Weathering, Mechanical Weathering
Erosion
No
Yes
Types of Erosion
Not Applicable
Chemical Erosion, Coastal Erosion, Glacier Erosion
Properties
Physical Properties
Hardness
6
6-7
Grain Size
Not Applicable
Fine Grained
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
White
Porosity
Less Porous
Highly Porous
Luster
Not Available
Dull
Compressive Strength
37.50 N/mm2
27
Not Available
Cleavage
Not Available
Not Available
Toughness
2.3
2.6
Specific Gravity
2.8-3
2.54-2.73
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
2.6-2.7 g/cm3
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K
15
Not Available
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Water Resistant
Reserves
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 Siltstone Properties
Know all about Variolite and Siltstone properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Siltstone belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Siltstone is Clastic. Variolite appears Dull and Soft and Siltstone appears Rough. The luster of Variolite is not available while that of Siltstone is dull. Variolite is available in black, brown, light to dark grey colors whereas Siltstone is available in brown, red, reddish brown colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Siltstone are raw material for the manufacture of mortar, soil conditioner.
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