Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
History
Origin
Indonesia
Webster, North Carolina
Discoverer
Cornish Gossen
Unknown
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
From the town of Webster located in North Carolina
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Rough, Sandy
Clastic, Granular, Phaneritic, Porphyritic
Color
Brown, Brown- Black, Gold, Green, Rust
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
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
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Translocated gossan and Leakage gossan
Ultramafic rock
Features
Clasts are smooth to touch, Easily splits into thin plates
Generally rough to touch, Is one of the oldest 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.
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Composition
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
Burial Metamorphism, Impact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
4-57
1
7
👆🏻
Grain Size
Fine to Medium Grained
Coarse Grained
Fracture
Conchoidal
Uneven
Streak
White to Grey
White, Greenish White or Grey
Porosity
Highly Porous
Less Porous
Luster
Metallic
Dull to Vitreous to Submetallic
Compressive Strength
-95.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
-
Specific Gravity
2.03.2-3.5
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
-9999 g/cm33.1-3.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.24 kJ/Kg K0.79 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Russia, Singapore, South Korea
India, Russia
Africa
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
South Africa
Europe
Albania, France, Germany, Great Britain, United Kingdom
Germany, Greece, Italy, Scotland, Turkey
Others
-
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil, Colombia, Ecuador
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, South Australia, Western Australia
New Zealand, Queensland