Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
Cornish Gossen
Unknown
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Rough, Sandy
Quench
Color
Brown, Brown- Black, Gold, Green, Rust
Black, Brown, Green, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Banded
Dull and Soft
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, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Antiquity Uses
Artifacts
Artifacts, Monuments
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
Creating Artwork, Gemstone
Types
Translocated gossan and Leakage gossan
Cataclastic rock
Features
Clasts are smooth to touch, Easily splits into thin plates
Host Rock for Lead
Archaeological Significance
Formation
Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
-
Grain Size
Fine to Medium Grained
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
White to Grey
Light to dark brown
Porosity
Highly Porous
Less Porous
Specific Gravity
2.0
2.46-2.86
Transparency
Opaque
Transparent to Translucent
Density
-9999 g/cm3
2.7-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Russia, Singapore, South Korea
South Korea
Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Western Africa
Europe
Albania, France, Germany, Great Britain, United Kingdom
Great Britain, Switzerland
Deposits in Western Continents
North America
Canada, USA
-
South America
Brazil, Colombia, Ecuador
-
Deposits in Oceania Continent
Australia
New South Wales, South Australia, Western Australia
Central Australia, Western Australia
All about Gossan and Pseudotachylite Properties
Know all about Gossan and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Gossan and Pseudotachylite belong to Metamorphic Rocks.Texture of Gossan is Rough, Sandy whereas that of Pseudotachylite is Quench. Gossan appears Dull and Banded and Pseudotachylite appears Dull and Soft. The luster of Gossan is metallic while that of Pseudotachylite is vitreous. Gossan is available in brown, brown- black, gold, green, rust colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Gossan are cemetery markers, commemorative tablets, gemstone and that of Pseudotachylite are creating artwork, gemstone.