Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Epidosite is a highly altered epidote and quartz bearing rock which is a type of metasomatite, essentially altered basalt
Discoverer
Unknown
Unknown
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
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Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Blue, Bluish - Grey
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Dull and Soft
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers
Commemorative Tablets, Creating Artwork
Types
Rhyolite
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Formation
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.
Epidosite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Albite, Amphibole, Quartz
Olivine, Plagioclase, Pyroxene
Compound Content
Al, Fe, Potassium Oxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Water Erosion
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Grain Size
Medium Grained
Fine to Coarse Grained
Fracture
Pervasive
Conchoidal
Streak
Bluish Black
White to Grey
Porosity
Highly Porous
Less Porous
Specific Gravity
2.38
2.8-3
Transparency
Opaque
Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
East Africa
South Africa
Deposits in Western Continents
North America
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Canada, USA
Deposits in Oceania Continent