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