Definition
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Discoverer
Edgar Bailey
Unknown
Etymology
From French schiste, Greek skhistos i.e. split
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Foliated
Porphyritic
Color
Blue, Bluish - Grey, Purple, Shades of Blue
Blue, Bluish - Grey
Durability
Durable
Durable
Appearance
Dull and Banded
Foliated
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones
Cemetery Markers
Types
Not Available
Rhyolite
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Used
Not Yet Used
Formation
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.
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz
Albite, Amphibole, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Al, Fe, Potassium Oxide
Types of Metamorphism
Not Applicable
Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Coastal Erosion, Water Erosion
Grain Size
Fine to Medium Grained
Medium Grained
Fracture
Conchoidal
Pervasive
Streak
White to Grey
Bluish Black
Porosity
Highly Porous
Highly Porous
Compressive Strength
Not Available
Cleavage
Slaty
Not Available
Specific Gravity
3-3.2
2.38
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
Not Available
Resistance
Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Africa
Egypt, Ethiopia, South Africa
East Africa
Europe
France, Greece, Iceland
Italy
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Not Yet Found
South America
Not Yet Found
Not Yet Found
Deposits in Oceania Continent
Australia
New Zealand
Queensland