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
  
Siltstone can be defined as a fine-grained sedimentary rock which mainly consists of consolidated silt
  
History
  
  
Origin
Egypt
  
Unknown
  
Discoverer
Georgius Agricola
  
Unknown
  
Etymology
From Late Latin Basaltes (variant of basanites ), very hard stone, which was imported from Ancient Greek Basanites
  
From English word silt and stone and from Proto-Indo-European root sal and stainaz
  
Class
Igneous Rocks
  
Sedimentary Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Volcanic
  
Not Applicable
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
  
Clastic
  
Color
Black, Brown, Light to Dark Grey
  
Brown, Red, Reddish Brown
  
Maintenance
More
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
No
  
Wind Resistant
No
  
Yes
  
Acid Resistant
Yes
  
Yes
  
Appearance
Dull and Soft
  
Rough
  
Architecture
  
  
Interior Uses
Floor Tiles, Homes, Hotels, Kitchens
  
Decorative Aggregates, Interior Decoration
  
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration, Office Buildings
  
As Building Stone, As Facing Stone, Garden Decoration
  
Other Architectural Uses
Curbing, Whetstones
  
Curbing
  
Industry
  
  
Construction Industry
Arrowheads, As Dimension Stone, Cobblestones, Cutting Tool, Rail Track Ballast, Roadstone
  
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments
  
Artifacts, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
An Oil and Gas Reservoir, Commemorative Tablets, Creating Artwork, Used in aquariums
  
Raw material for the manufacture of mortar, Soil Conditioner
  
Types
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
  
Not Available
  
Features
Has High structural resistance against erosion and climate, Very fine grained rock
  
Available in Lots of Colors and Patterns, Easily splits into thin plates, Generally rough to touch, High silica content, Very fine grained rock
  
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
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Present
  
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.
  
Siltstone is a type of sedimentary rock which is formed from fine rock particles. As the particles of eroded rock travel along with water, the edges of the rock are worn-out by water into a rounded shape.
  
Composition
  
  
Mineral Content
Olivine, Plagioclase, Pyroxene
  
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz, Sand, Silica, Silt
  
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, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
No
  
Types of Metamorphism
Contact Metamorphism
  
Not Applicable
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Available
  
Chemical Erosion, Coastal Erosion, Glacier Erosion
  
Physical Properties
  
  
Hardness
6
  
6-7
  
Grain Size
Fine Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
White to Grey
  
White
  
Porosity
Less Porous
  
Highly Porous
  
Luster
Not Available
  
Dull
  
Compressive Strength
37.40 N/mm
2
  
28
Not Available
  
Cleavage
Not Available
  
Not Available
  
Toughness
2.3
  
2.6
  
Specific Gravity
2.8-3
  
2.54-2.73
  
Transparency
Opaque
  
Opaque
  
Density
2.9-3.1 g/cm3
  
2.6-2.7 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.84 kJ/Kg K
  
15
Not Available
  
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Water Resistant
  
Deposits in Eastern Continents
  
  
Asia
India, Russia
  
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
  
Africa
South Africa
  
Namibia, Nigeria, South Africa
  
Europe
Iceland
  
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
  
Others
Not Yet Found
  
Greenland
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Brazil
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
Not Yet Found
  
New South Wales, New Zealand