They were followed by acicular-fibrous zeolites such as natrolite/ gonnardite, thomsonite, mesolite and scolecite Analcime is usually a Na-rich mineral phase, but may sometimes contain appreciable K (Utada, 1970).
They were followed by acicular-fibrous natrolite and Ca-rich zeolites such as gonnardite, thomsonite, mesolite and scolecite.
Back-scattered electron and secondary electron images of altered feldspathoids confirmed zones with different ratios of intimately intergrown thomsonite and gonnardite resembling primary feldspathoid zoning and shaping.
The presence of gonnardite in amygdules is problematic, however, a limited substitution of Ca for Na in natrolite was registered.
The presence of gonnardite is therefore questionable, because gonnardite was proved by no other independent diagnostic method.
Associated minerals are: microcline, nepheline (partially altered to natrolite), fluorite, natrolite, gonnardite
, rhodochrosite, aegirine, albite, calcite, serandite, ancylite-(Ce) and catapleiite.
Crystal-lined cavities contain albite, nabesite, gmelinite, neptunite, analcime, gonnardite
, lovdarite, an unidentified phase presumed to be trona and possibly opal.
Associated minerals are: aegirine, albite, analcime, ancylite-(Ce), calcite, catapleiite, dawsonite, donnayite-(Y), elpidite, epididymite, eudialyte, eudidymite, fluorite, franconite, gaidonnayite, galena, genthelvite, gmelinite, gonnardite
, horvathie-(Y), kupletskite, leifite, microcline, molybdenite, narsarsukite, natrolite, nenadkevichite, petersenite-(Ce), polylithionite, pyrochlore, quartz, rhodochrosite, rutile, sabinaite, serandite, siderite, sphalerite, thomasclarkite-(Y), zircon and an unidentified Na-REE-carbonate (UK91).
Associated minerals are: analcime, gonnardite
, vinogradovite, phillipsite, lavenite, seidozerite, fluorapatite, aegirine, potassic feldspar, nepheline, ilmenite, lorenzenite and sodalite.
In recent years there has been some question as to whether gonnardite
and tetranatrolite are separate species.