Analcime is found as an alteration product in diagenetically and hydrothermally altered rocks. Wairakite and analcime-wairakite solid solution occur commonly in the geothermal area.
Analcime-wairakite series mimerals which are analcime, wairakite and minerals having the intermediate chemical compositions occur in the Neogene system of the Nishi-Iburi district, southwest Hokkaido. In this paper, the mineralogical properties such as refractive indices, chemical composition, X-ray data and morphology are described. The wairakites in boring cores increase in Δ2θ(2θ₍₀₀₄₎-2θ₍₄₀₀₎) with increasing depth and temperature. This fact shows that Al/Si ordering of wairakite proceeds with a rise in temperature. Na₂O/CaO ratio of the analcime-wairakite series minerals decreases with burial depth. The plot of the minerals in natrolitewairakite-albite triangle diagram indicates that vacant immisicibility area in analcime-wairakite solid solution seems to be narrower than previous data.