Definition of phenocryst in English:
phenocryst
noun ˈfɛnə(ʊ)krɪstˈfiːnə(ʊ)krɪstˈfinəˌkrɪst
Geology A large or conspicuous crystal in a porphyritic rock, distinct from the groundmass.
Example sentencesExamples
- The majority of the rhyolites are porphyritic and contain phenocrysts of one or more of the following: plagioclase, clinopyroxene, magnetite, quartz and sanidine, plus accessory apatite and zircon.
- Rhyolite dykes, which are commonly porphyritic with phenocrysts of either plagioclase or quartz, are intruded by dykes of hornblende tonalite, and the gabbro is likewise intruded by tonalite dykes.
- Bulk tephra can include phenocrysts or xenocrysts, lithic fragments and other inclusions, the proportions of which may vary across the fallout area, making accurate correlation difficult.
- Orthoclase occurred as remnant phenocrysts in a groundmass of chloritic material resulting from alteration of iron-rich felsite cobbles.
- Pyroxene mineralogy evolves along two paths with near end-member hedenbergite phenocrysts in the groundmass and aegirine solid solution in miaroles.
Origin
Late 19th century: from French phénocryste, from Greek phainein 'to show' + krustallos 'crystal'.
Definition of phenocryst in US English:
phenocryst
nounˈfinəˌkrɪstˈfēnəˌkrist
Geology A large or conspicuous crystal in a porphyritic rock, distinct from the groundmass.
Example sentencesExamples
- The majority of the rhyolites are porphyritic and contain phenocrysts of one or more of the following: plagioclase, clinopyroxene, magnetite, quartz and sanidine, plus accessory apatite and zircon.
- Bulk tephra can include phenocrysts or xenocrysts, lithic fragments and other inclusions, the proportions of which may vary across the fallout area, making accurate correlation difficult.
- Pyroxene mineralogy evolves along two paths with near end-member hedenbergite phenocrysts in the groundmass and aegirine solid solution in miaroles.
- Rhyolite dykes, which are commonly porphyritic with phenocrysts of either plagioclase or quartz, are intruded by dykes of hornblende tonalite, and the gabbro is likewise intruded by tonalite dykes.
- Orthoclase occurred as remnant phenocrysts in a groundmass of chloritic material resulting from alteration of iron-rich felsite cobbles.
Origin
Late 19th century: from French phénocryste, from Greek phainein ‘to show’ + krustallos ‘crystal’.