Phonolite Thin Section

Phonolite

IUGS Definition ( QAPF Chart )

Phonolite: “A volcanic rock consisting essentially of alkali feldspar and any foids. If nepheline is the only foid then the term phonolite may be used by itself but if, for example, leucite is the most abundant foid then the term leucite phonolite should be used etc.”
Photos
Typical Minerals
  • sanidine
  • leucite