Definition
Trachyandesite is an extrusive igneous rock.
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Origin
Indonesia
Indonesia
Discoverer
Unknown
Cornish Gossen
Etymology
From French trachyandésite, trachy + andésite andesite, a lava intermediate in composition between trachyte and andesite
From Cornish gossen from gos, blood from Old Cornish guit
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Rough, Sandy
Color
Black, Brown, Light to Dark Grey
Brown, Brown- Black, Gold, Green, Rust
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Dull and Banded
Interior Uses
Countertops, Decorative Aggregates, Homes, 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, Cobblestones, for Road Aggregate, Rail Track Ballast, Roadstone
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Sculpture
Artifacts
Commercial Uses
Creating Artwork, Pottery
Cemetery Markers, Commemorative Tablets, Gemstone
Types
Basaltic Trachyandesite
Translocated gossan and Leakage gossan
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Clasts are smooth to touch, Easily splits into thin plates
Archaeological Significance
Formation
Trachyandesite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms 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
Alkali feldspar, Biotite, Olivine, Plagioclase, Pyroxene, Sodic plagioclase
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Grain Size
Fine Grained
Fine to Medium Grained
Fracture
Conchoidal
Conchoidal
Streak
Light to dark brown
White to Grey
Porosity
Less Porous
Highly Porous
Specific Gravity
2.8-3
2.0
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
India, Russia
China, India, Indonesia, Russia, Singapore, South Korea
Africa
South Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Europe
Iceland
Albania, France, Germany, Great Britain, United Kingdom
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
-
New South Wales, South Australia, Western Australia
All about Trachyandesite and Gossan Properties
Know all about Trachyandesite and Gossan properties here. All properties of rocks are important as they define the type of rock and its application. Trachyandesite belongs to Igneous Rocks while Gossan belongs to Metamorphic Rocks.Texture of Trachyandesite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Gossan is Rough, Sandy. Trachyandesite appears Dull and Soft and Gossan appears Dull and Banded. The luster of Trachyandesite is earthy while that of Gossan is metallic. Trachyandesite is available in black, brown, light to dark grey colors whereas Gossan is available in brown, brown- black, gold, green, rust colors. The commercial uses of Trachyandesite are creating artwork, pottery and that of Gossan are cemetery markers, commemorative tablets, gemstone.