Definition of amphibole in US English:

amphibole

noun

  • Any of a class of rock-forming silicate or aluminosilicate minerals typically occurring as fibrous or columnar crystals.

    • ‘The other two silicates are possibly an amphibole and a member of the smectite group.’
    • ‘During obduction, mantle-derived magmas most likely evolved to granitic compositions by assimilation of sediments and by fractional crystallization of amphibole, feldspar, titanite and allanite.’
    • ‘The greenschist-facies overprint resulted in the growth of actinolitic amphiboles, plagioclase and titanite at the expense of pyroxene and rutile or ilmenite.’
    • ‘Associated with the fayalite are quartz, amphibole, and magnetite.’
    • ‘They contain sulfide minerals as well as metamorphic minerals that include cordierite, gahnite, epidote, garnet, amphiboles, schorl, and many others.’

Origin

Early 19th century: from French, from Latin amphibolus ‘ambiguous’ (because of the varied structure of these minerals), from Greek amphibolos, from amphi- ‘both, on both sides’ + ballein ‘to throw’.

Pronunciation

amphibole

/ˈæmfəˌboʊl//ˈamfəˌbōl/