Definition
Basalt is a common extrusive igneous rock formed by the rapid cooling of basaltic lava exposed at or very near the surface of Earth
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
Georgius Agricola
Obsius
Etymology
From Late Latin Basaltes (variant of basanites ), very hard stone, which was imported from Ancient Greek Basanites
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
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Glassy
Color
Black, Brown, Light to Dark Grey
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Shiny
Interior Uses
Floor Tiles, Homes, Hotels, Kitchens
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration, Office Buildings
Garden Decoration
Other Architectural Uses
Curbing, Whetstones
Not Yet Used
Construction Industry
Arrowheads, As Dimension Stone, Cobblestones, Cutting Tool, Rail Track Ballast, Roadstone
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Not Yet Used
Surgery
Antiquity Uses
Artifacts, Monuments
Artifacts, Jewellery
Commercial Uses
An Oil and Gas Reservoir, Commemorative Tablets, Creating Artwork, Used in aquariums
Creating Artwork, Mirror, Used in aquariums
Types
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Easter Island in the Polynesian Triangle, Pacific Ocean, Gateway of India in Mumbai, India, Gol Gumbaz in Karnataka, India
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Figurines
Used
Not Yet Used
Formation
Basalt forms when lava reaches the Earth's surface near an active volcano. The temperature of lava is between 1100 to 1250° C when it gets to the surface.
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
Olivine, Plagioclase, Pyroxene
Not Available
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Not Available
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
Not Applicable
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
White
Porosity
Less Porous
Very Less Porous
Luster
Not Available
Vitreous
Cleavage
Not Available
Non-Existent
Toughness
2.3
Not Available
Specific Gravity
2.8-3
2.6-2.7
Transparency
Opaque
Translucent
Density
2.9-3.1 g/cm3
2.6 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
India, Russia
Afghanistan, Indonesia, Japan, Russia
Africa
South Africa
Kenya
Europe
Iceland
Greece, Hungary, Iceland, Italy, Turkey
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand
All about Basalt and Obsidian Properties
Know all about Basalt and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Basalt and Obsidian belong to Igneous Rocks.Texture of Basalt is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Obsidian is Glassy. Basalt appears Dull and Soft and Obsidian appears Shiny. The luster of Basalt is not available while that of Obsidian is vitreous. Basalt is available in black, brown, light to dark grey colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Basalt are an oil and gas reservoir, commemorative tablets, creating artwork, used in aquariums and that of Obsidian are creating artwork, mirror, used in aquariums.