noun
mass nounAny 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’- ‘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.’
- ‘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.’
- ‘The greenschist-facies overprint resulted in the growth of actinolitic amphiboles, plagioclase and titanite at the expense of pyroxene and rutile or ilmenite.’
- ‘The other two silicates are possibly an amphibole and a member of the smectite group.’
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’.
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