Definitions

from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A conspicuous, usually large, crystal embedded in porphyritic igneous rock.

from The Century Dictionary.

  • noun One of the prominent crystals in a porphyritic rock.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Geol.) One of the prominent embedded crystals of a porphyry.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun mineralogy any relatively large crystal embedded in a more fine-grained or glassy igneous rock

Etymologies

from The American Heritage® Dictionary of the English Language, 4th Edition

[pheno– + cryst(al).]

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Examples

  • Fig. 9 (A, B) shows an MI believed to have formed as a two-phase mixed inclusion (melt + fluid) within a quartz phenocryst of peralkaline rhyolite (Lowenstern et al. 1991).

    Evidence for Fluid Saturation and Degassing 2008

  • Quartz in groundmass does not appear to have nucleated directly on phenocryst, but is in optical continuity with it. (f) Primary vapor-rich fluid inclusion in phenocrystic quartz.

    granophyre_photos.html 1998

  • Radiating fringe of feldspar in groundmass is in optical continuity with phenocryst, from which it nucleated. (e) Quartz phenocryst is surrounded by feldspar groundmass.

    granophyre_photos.html 1998

  • Figure parts a-e with crossed nichols. (a) Micrographic groundmass surrounds feldspar phenocryst fragment. (b) Micrographic groundmass around clinopyroxene phenocryst.

    granophyre_photos.html 1998

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