The heat treatment of some Norwegian aventurinized feldspars

ABSTRACT. The morphology and structures of inter-growth precipitates in some Norwegian aventurinized plagioclases have been described inprevious publications; data collected uring an investigation f a wide variety of heat treatments upon the same specimens are now reported. In detail the behaviour of different feldspar crystals i highly individualistic, though there is a com-mon pattern in sub-solidus reaction(s) with the feldspar; even if the identification ofthe products is uncertain, it is this process which causes the apparent 'homogeniza-tion ' of the feldspar. Some comparisons can be made between the present studies and the more limited experiments of earlier workers, and suggestions for reconciling experimental data are discussed. On the paragenesis of aventurinize