A hypabyssal rock composed essentially of large phenocrysts of alkalic feldspar,
sodic pyroxene, amphibole, and nepheline with smaller phenocrysts of accessory
olivine. Feldspar, pyroxene, and amphibole recur in the groundmass. A
porphyritic variety of olivine-bearing phonolite. Syn:
uraninite
Source:
Dictionary of Mining, Mineral, and Related Terms
