basalt
UK[ˈbæsɔːlt]US[bəˈsɔːlt]
n
A dark, fine-grained volcanic rock formed from the rapid cooling of lava.
Etymology
The word 'basalt' entered English in the early 17th century from the Latin basaltes, a misspelling or variant of basanites, meaning 'very hard stone'. This Latin term was itself borrowed from the Greek basanitēs (lithos), meaning 'touchstone', a stone used for testing gold and silver. The Greek word derived from basanos, meaning 'touchstone' or 'test', which is thought to have an Egyptian origin. Thus, the modern geological term for a specific volcanic rock evolved from an ancient word for a stone used to test the purity of precious metals, reflecting a shared characteristic of hardness.
Analysis
The word 'basalt' is a simplex loanword. It does not contain separable morphemes in its modern English spelling that carry independent meaning.
Examples
The Giant's Causeway in Northern Ireland is famous for its interlocking columns of basalt.
The dark plains on the Moon, known as maria, are primarily composed of basalt.
The road was constructed using crushed basalt for its durability.