Definition of amphibole in English:



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

    ‘acid rocks consist mostly of quartz and feldspars, with a little mica or amphibole’
    • ‘Associated with the fayalite are quartz, amphibole, and magnetite.’
    • ‘The other two silicates are possibly an amphibole and a member of the smectite group.’
    • ‘The greenschist-facies overprint resulted in the growth of actinolitic amphiboles, plagioclase and titanite at the expense of pyroxene and rutile or ilmenite.’
    • ‘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.’
    • ‘They contain sulfide minerals as well as metamorphic minerals that include cordierite, gahnite, epidote, garnet, amphiboles, schorl, and many others.’


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.