Primary Igneous Analcite--an Experimental Study

Abstract

In the albite-orthoclase-nepheline-kalsilite-water system the assemblage analcite-melt (±nepheline albite and orthoclase) can only exist in the pressure range 5 to 13 Kbars and at temperatures between 640 and 600 °C. Primary igneous analcite will have a similar restricted PT range which probably means that interstitial analcite found in many high-level dike rocks is secondary.