Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition
History
Origin
Indonesia
-
Discoverer
Cornish Gossen
Unknown
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
From English feldspar and -ite
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Rough, Sandy
Arborescent Patterned, Vitreous
Color
Brown, Brown- Black, Gold, Green, Rust
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull and Banded
Layered, Banded, Veined and Shiny
Architecture
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
-
Surgery
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
Mirror, Jewelry
Types
Translocated gossan and Leakage gossan
Igneous rock
Features
Clasts are smooth to touch, Easily splits into thin plates
Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, Very fine grained rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.
Felsite 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.
Composition
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Feldspar, Iron Oxides
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Chemical Erosion, Glacier Erosion, Water Erosion
Physical Properties
Hardness
4-55-5.5
1
7
👆🏻
Grain Size
Fine to Medium Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
White
Porosity
Highly Porous
Very Less Porous
Luster
Metallic
Vitreous
Compressive Strength
-0.15 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
-
Specific Gravity
2.02.6-2.7
0
8.4
👆🏻
Transparency
Opaque
Translucent
Density
-9999 g/cm32.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.24 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Russia, Singapore, South Korea
Afghanistan, Indonesia, Japan, Russia
Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Kenya
Europe
Albania, France, Germany, Great Britain, United Kingdom
Greece, Hungary, Iceland, Italy, Turkey
Others
-
-
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil, Colombia, Ecuador
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, South Australia, Western Australia
New Zealand