Compositional heterogeneity of pollucite from High Grade Dyke, Maskwa Lake, southeastern Manitoba

Primary pollucite from the High Grade Dyke pegmatite of the Maskwa Lake group in southeastern Manitoba occurs with spodumene, microcline, quartz, elbaite, albite, and lepidolite. Pollucite is replaced en masse by microcline and lepidolite + quartz, veined by a sequence of spodumene, lepidolite, late spodumene and adularia, and replaced at a late stage by clay minerals. The primary homogeneous pollucite has locally evolved to a mosaic of Na-enriched and Cs-enriched domains 20-300 JLm across, cross-cut by 1-to 15-JLm veinlets of quartz-containin g Cs-rich pollucite