Definition
Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
Discoverer
Unknown
Obsius
Etymology
From Old French pomis, from a Latin dialect variant of pumex
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
Color
Beige, Grey, Light Green, Light Grey, Pink, White, Yellow- grey
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Vesicular
Shiny
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Garden Decoration
Other Architectural Uses
Curbing, Powder
-
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
Surgery
Antiquity Uses
Artifacts
Artifacts, Jewellery
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
Creating Artwork, Mirror, Used in aquariums
Types
Scoria
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Host Rock for Lead
Blocks negativity, Helps to protect against depression
Archaeological Significance
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.
When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.
Mineral Content
Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica
-
Compound Content
Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Impact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
-
Fracture
Planar
Conchoidal
Streak
White, Greenish White or Grey
White
Porosity
Highly Porous
Very Less Porous
Specific Gravity
2.86
2.6-2.7
Transparency
Opaque
Translucent
Density
0.25-0.3 g/cm3
2.6 g/cm3
Resistance
Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Afghanistan, Indonesia, Japan, Russia
Africa
Ethiopia, Kenya, Tanzania
Kenya
Europe
Greece, Hungary, Iceland, Italy, Turkey
Greece, Hungary, Iceland, Italy, Turkey
Deposits in Western Continents
North America
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA
Canada, Mexico, USA
South America
Argentina, Chile, Ecuador, Peru
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
New Zealand
Pumice vs Obsidian Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Pumice vs Obsidian characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Pumice and Properties of Obsidian. Learn more about Pumice vs Obsidian in the next section. The interior uses of Pumice include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Obsidian include Decorative aggregates and Interior decoration. Due to some exceptional properties of Pumice and Obsidian, they have various applications in construction industry. The uses of Pumice in construction industry include As dimension stone, Cement manufacture, For road aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks and that of Obsidian include Arrowheads, Cutting tool, Knives, Scrapers, Spear points.
More about Pumice and Obsidian
Here you can know more about Pumice and Obsidian. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Pumice and Obsidian consists of mineral content and compound content. The mineral content of Pumice includes Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica and mineral content of Obsidian includes . You can also check out the list of all Igneous Rocks. When we have to compare Pumice vs Obsidian, the texture, color and appearance plays an important role in determining the type of rock. Pumice is available in beige, grey, light green, light grey, pink, white, yellow- grey colors whereas, Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. Appearance of Pumice is Vesicular and that of Obsidian is Shiny. Properties of rock is another aspect for Pumice vs Obsidian. The hardness of Pumice is 6 and that of Obsidian is 5-5.5. The types of Pumice are Scoria whereas types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Pumice and Obsidian is white, greenish white or grey. The specific heat capacity of Pumice is 0.87 kJ/Kg K and that of Obsidian is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Pumice is impact resistant, pressure resistant whereas Obsidian is heat resistant, impact resistant.