Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
History
Origin
Italy
USA
Discoverer
Unknown
Unknown
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
-
Other Categories
Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Quench
Color
Blue, Bluish - Grey
Black, Brown, Green, Grey, Pink, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Foliated
Dull and Soft
Architecture
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
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, Cement Manufacture, for Road Aggregate, Making natural cement
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts, Monuments
Other Uses
Commercial Uses
Cemetery Markers
Creating Artwork, Gemstone
Types
Rhyolite
Cataclastic rock
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Host Rock for Lead
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
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.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Composition
Mineral Content
Albite, Amphibole, Quartz
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Al, Fe, Potassium Oxide
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Coastal Erosion, Water Erosion
-
Physical Properties
Hardness
6-77
1
7
👆🏻
Grain Size
Medium Grained
Very fine-grained
Fracture
Pervasive
Uneven
Streak
Bluish Black
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Dull
Vitreous
Compressive Strength
92.40 N/mm260.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
2
-
Specific Gravity
2.382.46-2.86
0
8.4
👆🏻
Transparency
Opaque
Transparent to Translucent
Density
-9999 g/cm32.7-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.79 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China
South Korea
Africa
East Africa
Western Africa
Europe
Italy
Great Britain, Switzerland
Others
-
-
Deposits in Western Continents
North America
-
-
South America
-
-
Deposits in Oceania Continent
Australia
Queensland
Central Australia, Western Australia