Gossan and Comendite
Definition
Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
History
Origin
Indonesia
Italy
Discoverer
Cornish Gossen
Unknown
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
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
Family
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Texture
Rough, Sandy
Porphyritic
Color
Brown, Brown- Black, Gold, Green, Rust
Blue, Bluish - Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
Yes
Yes
Wind Resistant
No
Yes
Acid Resistant
No
Yes
Appearance
Dull and Banded
Foliated
Uses
Architecture
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
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
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
Cemetery Markers
Types
Types
Translocated gossan and Leakage gossan
Rhyolite
Features
Clasts are smooth to touch, Easily splits into thin plates
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Not Yet Used
Fossils
Absent
Absent
Formation
Formation
Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.
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.
Composition
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Albite, Amphibole, Quartz
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Al, Fe, Potassium Oxide
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Cataclastic Metamorphism, Regional Metamorphism
Weathering
No
Yes
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Coastal Erosion, Water Erosion
Properties
Physical Properties
Hardness
4-5
6-7
Grain Size
Fine to Medium Grained
Medium Grained
Fracture
Conchoidal
Pervasive
Streak
White to Grey
Bluish Black
Porosity
Highly Porous
Highly Porous
Luster
Metallic
Dull
Compressive Strength
Not Available
92.40 N/mm2
21
Cleavage
Not Available
Not Available
Toughness
Not Available
2
Specific Gravity
2.0
2.38
Transparency
Opaque
Opaque
Density
Not Available
Not Available
Thermal Properties
Specific Heat Capacity
0.24 kJ/Kg K
24
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Indonesia, Russia, Singapore, South Korea
China
Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
East Africa
Europe
Albania, France, Germany, Great Britain, United Kingdom
Italy
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Not Yet Found
South America
Brazil, Colombia, Ecuador
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, South Australia, Western Australia
Queensland
All about Gossan and Comendite Properties
Know all about Gossan and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Gossan belongs to Metamorphic Rocks while Comendite belongs to Igneous Rocks.Texture of Gossan is Rough, Sandy whereas that of Comendite is Porphyritic. Gossan appears Dull and Banded and Comendite appears Foliated. The luster of Gossan is metallic while that of Comendite is dull. Gossan is available in brown, brown- black, gold, green, rust colors whereas Comendite is available in blue, bluish - grey colors. The commercial uses of Gossan and Comendite are cemetery markers, commemorative tablets, gemstone.
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