Variolite and Phyllite
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
Phyllite is a fine-grained metamorphic rock with a well-developed laminar structure, and is intermediate between slate and schist rocks
History
Origin
France
Unknown
Discoverer
Unknown
Unknown
Etymology
From Latin varius, speckled, variegated
From Greek phullon leaf + -ite1
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Phyllitic Sheen, Slaty
Color
Black, Brown, Light to Dark Grey
Black to Grey, Light Greenish Grey
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
No
No
Wind Resistant
No
No
Acid Resistant
Yes
No
Appearance
Dull and Soft
Crinkled or Wavy
Uses
Architecture
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Decorative Aggregates, Floor Tiles, Homes, 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
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture
Other Uses
Commercial Uses
Cemetery Markers, Creating Artwork
Cemetery Markers, Commemorative Tablets, Creating Artwork, 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, Is one of the oldest rock, Surfaces are often shiny
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
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.
Phyllite is a metamorphic rock which is formed by regional metamorphism of argillaceous sediments since their cleavage arose due to deviatoric stress.
Composition
Mineral Content
Olivine, Plagioclase, Pyroxene
Albite, Alusite, Amphibole, Apatite, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
CaO, Carbon Dioxide, MgO
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, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
6
1-2
Grain Size
Not Applicable
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
White
Porosity
Less Porous
Highly Porous
Luster
Not Available
Phyllitic
Compressive Strength
37.50 N/mm2
27
Not Available
Cleavage
Not Available
Crenulation and Pervasive
Toughness
2.3
1.2
Specific Gravity
2.8-3
2.72-2.73
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
2.18-3.3 g/cm3
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K
15
Not Available
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Water Resistant
Reserves
Deposits in Eastern Continents
Asia
India, Russia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
Africa
South Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Europe
Iceland
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
Brazil
Brazil, Colombia, Guyana
Deposits in Oceania Continent
Australia
Not Yet Found
New South Wales, New Zealand, Queensland
All about Variolite and Phyllite Properties
Know all about Variolite and Phyllite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Phyllite belongs to Metamorphic Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Phyllite is Phyllitic Sheen, Slaty. Variolite appears Dull and Soft and Phyllite appears Crinkled or Wavy. The luster of Variolite is not available while that of Phyllite is phyllitic. Variolite is available in black, brown, light to dark grey colors whereas Phyllite is available in black to grey, light greenish grey colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Phyllite are cemetery markers, commemorative tablets, creating artwork, writing slates.
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