Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Rhyolite is a fine-grained igneous rock which is rich in silica
History
Origin
Indonesia
North America
Discoverer
Cornish Gossen
Ferdinand von Richthofen
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
Volcanic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Rough, Sandy
Aphanitic, Glassy, Porphyritic
Color
Brown, Brown- Black, Gold, Green, Rust
Grey, White, Light Black
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull and Banded
Banded
Architecture
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
Gemstone, Laboratory bench tops, Jewelry
Types
Translocated gossan and Leakage gossan
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Features
Clasts are smooth to touch, Easily splits into thin plates
Acidic in nature, Available in lots of colors
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.
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
Composition
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Cataclastic 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, Sea Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
4-56-7
1
7
👆🏻
Grain Size
Fine to Medium Grained
Large and Coarse Grained
Fracture
Conchoidal
Sub-conchoidal
Streak
White to Grey
-
Porosity
Highly Porous
Highly Porous
Luster
Metallic
Earthy
Compressive Strength
-140.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
2
Specific Gravity
2.02.65-2.67
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
-9999 g/cm32.4-2.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.24 kJ/Kg K0.71 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Russia, Singapore, South Korea
China, India
Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Albania, France, Germany, Great Britain, United Kingdom
Germany, Iceland, Ireland, Italy, Spain
Others
-
-
Deposits in Western Continents
North America
Canada, USA
Canada, 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, Queensland, Western Australia