Definition
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
Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Old French pomis, from a Latin dialect variant of pumex
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Beige, Colourless, Grey, Light Green, Light Grey, Pink, White, Yellow- grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Vesicular
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Not Yet Used
Curbing, Powder
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks
Medical Industry
Surgery
As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
Antiquity Uses
Artifacts, Jewellery
Artifacts
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
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
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Scoria
Features
Blocks negativity, Helps to protect against depression
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
Figurines
Not Yet Used
Not Yet Used
Formation
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.
Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.
Mineral Content
Not Available
Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Impact 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
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Not Applicable
Fine Grained
Fracture
Conchoidal
Planar
Streak
White
White, Greenish White or Grey
Porosity
Very Less Porous
Highly Porous
Cleavage
Non-Existent
Perfect
Toughness
Not Available
3
Specific Gravity
2.6-2.7
2.86
Transparency
Translucent
Opaque
Density
2.6 g/cm3
0.25-0.3 g/cm3
Resistance
Heat Resistant, Impact Resistant
Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Afghanistan, Indonesia, Japan, Russia
Africa
Kenya
Ethiopia, Kenya, Tanzania
Europe
Greece, Hungary, Iceland, Italy, Turkey
Greece, Hungary, Iceland, Italy, Turkey
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA
South America
Argentina, Chile, Ecuador, Peru
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New Zealand
New Zealand, Western Australia
Obsidian vs Pumice 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. Obsidian vs Pumice characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Pumice. Learn more about Obsidian vs Pumice in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Pumice include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Obsidian and Pumice, they have various applications in construction industry. The uses of Obsidian in construction industry include Arrowheads, Cutting tool, Knives, Scrapers, Spear points and that of Pumice include As dimension stone, Cement manufacture, For road aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks.
More about Obsidian and Pumice
Here you can know more about Obsidian and Pumice. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Pumice consists of mineral content and compound content. The mineral content of Obsidian is not available and mineral content of Pumice includes Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Pumice, the texture, color and appearance plays an important role in determining the type of rock. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas, Pumice is available in beige, colourless, grey, light green, light grey, pink, white, yellow- grey colors. Appearance of Obsidian is Shiny and that of Pumice is Vesicular. Properties of rock is another aspect for Obsidian vs Pumice. The hardness of Obsidian is 5-5.5 and that of Pumice is 6. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Pumice are Scoria. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Obsidian is white while that of Pumice is white, greenish white or grey. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Pumice is 0.87 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Obsidian is heat resistant, impact resistant whereas Pumice is impact resistant, pressure resistant.