The following associations of zeolytic phases were determined: laumontite + chabazite; wairakite + chabazite; chabazite + thomsonite; analcime + thomsonite; thomsonite + wairakite + chabazite; thomsonite + analcime + chabazite; natrolite + analcime + thomsonite.
No regional zoning of zeolite assemblages was apparent in this study Figure 8 shows that the zoning sequence and textural evidence suggest the following crystallisation sequence: first K-rich clay (nontronite) followed by K-rich mica (celadonite), carbonate (calcite), cryptocrystalline silica (e g chalcedony), then thomsonite followed by chabazite, analcime, phillipsite and wairakite, and natrolite, laumontite, and stilbite-type minerals (stilbite and stellerite) Zeolites' stability ields are known from modern hydrothermal systems (Kristmannsdottir and Tomasson, 1978) and the observed sequence in the samples studied here conformed to a progressive decrease in temperature favouring hydrothermal system hydration.
Thomsonite is the most common zeolite phase formed after nontronite/celadonite Chabazite, analcime, phillipsite and probably wairakite are the irst zeolites which became crystallised.
Thomsonite was the most common zeolite phase formed after nontronite/celadonite Na-rich zeolites such as chabazite, analcime, phillipsite and probably wairakite were the first zeolites that became crystallised.
Structural classification Identified zeolitic phases Heulandite group (C4-C4-T1) stellerite, stilbite, stellerite-Na, Stilbite-Ca Chabazite group (C6) chabazite, levyne, chabazite-Ca, chabazite-Na Analcime group (C4-C4) analcime, wairakite, analcime-Mg Natrolite group (C4-T1) natrolite, thomsonite, thomsonite-Ca Phillipsite group (C4) phillipsite, phillipsite-Na Laumontite group (C8) laumontite
The deep-sea volcanogenic accumulations interlayered with basalt effusives contain the following secondary silicates in semiquantitative relations: saponite > analcime, wairakite
> chlorite, actinolite, tremolite > heulandite, clinoptilolite (?
The most common minerals present in the deposits are mordenite, clinoptilolite, laumonite, and wairakite
They are "heulandite" (heulandite sensu stricto and clinoptilolite), chabazite, analcime, stilbite, barrerite, epistilbite, gmelinite, laumontite, natrolite, mesolite, scolecite, stellerite, tetranatrolite, thomsonite, and wairakite.
Wairakite is generally vitreous with well formed pseudo-octahedral to pseudo-icositetrahedral colourless crystals that can be confused with analcime (Fig.
Tetranatrolite, stellerite, barrerite, scolecite, and wairakite have also been identified.
Thomsonite, mesolite, and wairakite have narrow compositional ranges.
In contrast, on the North Shore, all epistilbite, thomsonite, and mesolite analyses lie in this field, together with wairakite and many chabazite analyses, two minerals not analyzed from Kings County.