Gossan and Dacite
Definition
Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
History
Origin
Indonesia
Romania and Moldova, Europe
Discoverer
Cornish Gossen
Unknown
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Texture
Rough, Sandy
Aphanitic to Porphyritic
Color
Brown, Brown- Black, Gold, Green, Rust
Bluish - Grey, Brown, Grey, Light to Dark Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
Yes
No
Wind Resistant
No
No
Acid Resistant
No
No
Appearance
Dull and Banded
Vesicular
Uses
Architecture
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
Commemorative Tablets, Creating Artwork
Types
Types
Translocated gossan and Leakage gossan
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Clasts are smooth to touch, Easily splits into thin plates
Host Rock for Lead, Is one of the oldest 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
Used
Petroglyphs
Used
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.
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Composition
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic 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
Chemical Erosion
Properties
Physical Properties
Hardness
4-5
2-2.25
Grain Size
Fine to Medium Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
White
Porosity
Highly Porous
Less Porous
Luster
Metallic
Subvitreous to Dull
Cleavage
Not Available
Perfect
Toughness
Not Available
Not Available
Specific Gravity
2.0
2.86-2.87
Transparency
Opaque
Translucent
Density
Not Available
2.77-2.771 g/cm3
Thermal Properties
Specific Heat Capacity
0.24 kJ/Kg K
24
0.92 kJ/Kg K
10
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
China, India, Indonesia, Russia, Singapore, South Korea
Not Yet Found
Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Not Yet Found
Europe
Albania, France, Germany, Great Britain, United Kingdom
France, Greece, Romania, Scotland, Spain
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil, Colombia, Ecuador
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, South Australia, Western Australia
New Zealand, South Australia, Western Australia
All about Gossan and Dacite Properties
Know all about Gossan and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Gossan belongs to Metamorphic Rocks while Dacite belongs to Igneous Rocks.Texture of Gossan is Rough, Sandy whereas that of Dacite is Aphanitic to Porphyritic. Gossan appears Dull and Banded and Dacite appears Vesicular. The luster of Gossan is metallic while that of Dacite is subvitreous to dull. Gossan is available in brown, brown- black, gold, green, rust colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Gossan are cemetery markers, commemorative tablets, gemstone and that of Dacite are commemorative tablets, creating artwork.
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