Definition
Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
History
Origin
Spain
Indonesia
Discoverer
Unknown
Cornish Gossen
Etymology
From Old French pomis, from a Latin dialect variant of pumex
From Cornish gossen from gos, blood from Old Cornish guit
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Vesicular
Rough, Sandy
Color
Beige, Grey, Light Green, Light Grey, Pink, White, Yellow- grey
Brown, Brown- Black, Gold, Green, Rust
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Vesicular
Dull and Banded
Architecture
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing, Powder
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
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
Cemetery Markers, Commemorative Tablets, Gemstone
Types
Scoria
Translocated gossan and Leakage gossan
Features
Host Rock for Lead
Clasts are smooth to touch, Easily splits into thin plates
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.
Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.
Composition
Mineral Content
Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Compound Content
Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
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, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Physical Properties
Hardness
64-5
1
7
👆🏻
Grain Size
Fine Grained
Fine to Medium Grained
Fracture
Planar
Conchoidal
Streak
White, Greenish White or Grey
White to Grey
Porosity
Highly Porous
Highly Porous
Luster
Earthy
Metallic
Compressive Strength
51.20 N/mm2-
0.15
450
👆🏻
Cleavage
Perfect
-
Toughness
3
-
Specific Gravity
2.862.0
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
0.25-0.3 g/cm3-9999 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.87 kJ/Kg K0.24 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
China, India, Indonesia, Russia, Singapore, South Korea
Africa
Ethiopia, Kenya, Tanzania
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Albania, France, Germany, Great Britain, United Kingdom
Others
-
-
Deposits in Western Continents
North America
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
New South Wales, South Australia, Western Australia