Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Discoverer
Unknown
Cornish Gossen
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From Cornish gossen from gos, blood from Old Cornish guit
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Medium Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Porphyritic
Rough, Sandy
Color
Blue, Bluish - Grey
Brown, Brown- Black, Gold, Green, Rust
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Dull and Banded
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
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, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers
Cemetery Markers, Commemorative Tablets, Gemstone
Types
Rhyolite
Translocated gossan and Leakage gossan
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Clasts are smooth to touch, Easily splits into thin plates
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.
Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.
Mineral Content
Albite, Amphibole, Quartz
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Compound Content
Al, Fe, Potassium Oxide
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Coastal Erosion, Water Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Grain Size
Medium Grained
Fine to Medium Grained
Fracture
Pervasive
Conchoidal
Streak
Bluish Black
White to Grey
Porosity
Highly Porous
Highly Porous
Specific Gravity
2.38
2.0
Transparency
Opaque
Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China
China, India, Indonesia, Russia, Singapore, South Korea
Africa
East Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Europe
Italy
Albania, France, Germany, Great Britain, United Kingdom
Deposits in Western Continents
North America
-
Canada, USA
South America
-
Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
Queensland
New South Wales, South Australia, Western Australia