Basalt

Main Elements:

Si, Al, Fe, Mg, Ca, Na, K, O

Chemical Composition:

SiO₂ 45-52%, Al₂O₃ 14-18%, FeO 5-14%, MgO 5-12%, CaO 8-12%, Na₂O 2-5%, K₂O 0.5-2%, TiO₂ 1-3%

Density:

2.8 – 3.0 g/cm³

Compressive Strength:

100 – 300 MPa

Melting Point:

1000 – 1200°C

Formation:

Forms from rapidly cooled lava flows, either on the surface (extrusive) or in shallow intrusions. Most common rock type on ocean floors.

Composition:

Composed mainly of plagioclase feldspar and pyroxene minerals, with olivine and magnetite.

Types:

• Tholeiitic Basalt
• Alkaline Basalt
• High-alumina Basalt

Etymology:

Derived from the Latin word "basaltes", possibly from an ancient Ethiopian word meaning "black stone".

Uses:

• Road construction
• Concrete aggregate
• Railway ballast
• Ancient tools
• Building stone

Distribution:

Found worldwide, especially in volcanic regions and ocean floors

Historical Use:

Used by ancient peoples for tools and weapons. The Giant's Causeway in Ireland is a famous basalt formation.

Symbolism:

Represents volcanic power and Earth's dynamic nature

What is basalt used for?

Basalt is commonly used in road construction, as concrete aggregate, railway ballast, and in building materials due to its durability.

Where is basalt found?

Basalt is found worldwide, especially in volcanic regions like Iceland, Hawaii, and India. It forms most of the ocean floor.

Is basalt magnetic?

Yes, basalt can be magnetic due to its iron content, particularly magnetite minerals within the rock.

How does basalt form?

Basalt forms when lava cools rapidly, either on the Earth's surface or in shallow intrusions, preventing large crystals from forming.