Definition
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
  
Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals
  
History
  
  
Origin
Indonesia
  
Spain
  
Discoverer
Cornish Gossen
  
Unknown
  
Etymology
From Cornish gossen from gos, blood from Old Cornish guit
  
From Old French pomis, from a Latin dialect variant of pumex
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Rough, Sandy
  
Vesicular
  
Color
Brown, Brown- Black, Gold, Green, Rust
  
Beige, Colourless, Grey, Light Green, Light Grey, Pink, White, Yellow- grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
Yes
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
Yes
  
Appearance
Dull and Banded
  
Vesicular
  
Architecture
  
  
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
  
Decorative Aggregates, Flooring, Homes, 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, Powder
  
Industry
  
  
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
  
As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks
  
Medical Industry
Not Yet Used
  
As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
  
Antiquity Uses
Artifacts
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Cemetery Markers, Commemorative Tablets, Gemstone
  
As a traction material on snow-covered roads, As an abrasive in pencil erasers, Fine abrasive used for polishing, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Used in aquariums
  
Types
Translocated gossan and Leakage gossan
  
Scoria
  
Features
Clasts are smooth to touch, Easily splits into thin plates
  
Host Rock for Lead
  
Archaeological Significance
  
  
Monuments
Not Yet Used
  
Not Yet Used
  
Famous Monuments
Not Applicable
  
Not Applicable
  
Sculpture
Not Yet Used
  
Not Yet Used
  
Famous Sculptures
Not Applicable
  
Not Applicable
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Not Yet Used
  
Not Yet Used
  
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.
  
Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.
  
Composition
  
  
Mineral Content
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
  
Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica
  
Compound Content
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
  
Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Impact Metamorphism
  
Weathering
No
  
Yes
  
Types of Weathering
Not Applicable
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
4-5
  
6
  
Grain Size
Fine to Medium Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Planar
  
Streak
White to Grey
  
White, Greenish White or Grey
  
Porosity
Highly Porous
  
Highly Porous
  
Luster
Metallic
  
Earthy
  
Compressive Strength
Not Available
  
51.20 N/mm
2
  
26
Cleavage
Not Available
  
Perfect
  
Toughness
Not Available
  
3
  
Specific Gravity
2.0
  
2.86
  
Transparency
Opaque
  
Opaque
  
Density
Not Available
  
0.25-0.3 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.24 kJ/Kg K
  
24
0.87 kJ/Kg K
  
14
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
  
Impact Resistant, Pressure 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
  
Ethiopia, Kenya, Tanzania
  
Europe
Albania, France, Germany, Great Britain, United Kingdom
  
Greece, Hungary, Iceland, Italy, Turkey
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, 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, Western Australia