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Variolite and Blueschist


Blueschist and Variolite


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   
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature   

History
  
  

Origin
France   
USA   

Discoverer
Unknown   
Edgar Bailey   

Etymology
From Latin varius, speckled, variegated   
From French schiste, Greek skhistos i.e. split   

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, Medium Grained Rock, Opaque Rock   

Texture

Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular   
Foliated   

Color
Black, Brown, Light to Dark Grey   
Blue, Bluish - Grey, Purple, Shades of Blue   

Maintenance
Less   
Less   

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   
Dull and Banded   

Uses

Architecture
  
  

Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens   
Floor Tiles, Flooring, Homes, Hotels, Kitchens   

Exterior Uses
Garden Decoration, Office Buildings   
Garden Decoration, Office Buildings   

Other Architectural Uses
Curbing   
Not Yet Used   

Industry
  
  

Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone   
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts, Monuments, Sculpture   
Artifacts, Monuments, Sculpture   

Other Uses
  
  

Commercial Uses
Cemetery Markers, Creating Artwork   
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones   

Types

Types
Not Available   
Not Available   

Features
Has High structural resistance against erosion and climate, Very fine grained rock   
Has High structural resistance against erosion and climate, 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.   
Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.   

Composition
  
  

Mineral Content
Olivine, Plagioclase, Pyroxene   
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, 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, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium 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   
Mechanical Weathering   

Erosion
No   
Yes   

Types of Erosion
Not Applicable   
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion   

Properties

Physical Properties
  
  

Hardness
6   
3.5-4   

Grain Size
Not Applicable   
Fine to Medium Grained   

Fracture
Conchoidal   
Conchoidal   

Streak
White to Grey   
White to Grey   

Porosity
Less Porous   
Highly Porous   

Luster
Not Available   
Dull   

Compressive Strength
37.50 N/mm2   
27
Not Available   

Cleavage
Not Available   
Slaty   

Toughness
2.3   
1.5   

Specific Gravity
2.8-3   
3-3.2   

Transparency
Opaque   
Opaque   

Density
2.9-3.1 g/cm3   
2.8-2.9 g/cm3   

Thermal Properties
  
  

Specific Heat Capacity
0.84 kJ/Kg K   
15
Not Available   

Resistance
Heat Resistant, Pressure Resistant, Wear Resistant   
Impact Resistant, Pressure Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
India, Russia   
Japan, Turkey   

Africa
South Africa   
Egypt, Ethiopia, South Africa   

Europe
Iceland   
France, Greece, Iceland   

Others
Not Yet Found   
Not Yet Found   

Deposits in Western Continents
  
  

North America
Canada, USA   
USA   

South America
Brazil   
Not Yet Found   

Deposits in Oceania Continent
  
  

Australia
Not Yet Found   
New Zealand   

Summary >>
<< Reserves

All about Variolite and Blueschist Properties

Know all about Variolite and Blueschist properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Blueschist belongs to Metamorphic Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Blueschist is Foliated. Variolite appears Dull and Soft and Blueschist appears Dull and Banded. The luster of Variolite is not available while that of Blueschist is dull. Variolite is available in black, brown, light to dark grey colors whereas Blueschist is available in blue, bluish - grey, purple, shades of blue colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Blueschist are cemetery markers, commemorative tablets, creating artwork, curling, tombstones.

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