Relationship of Anomalous Fading to Feldspar Inclusions in Quartz

Abstract The potential relationship between feldspar inclusions and anomalous fading in quartz is examined. Using scanning electron microscopy and electron microprobe observations, feldspar inclusions are observed to occur in natural quartz grains taken from a variety of locations. Anomalous fading in these samples is compared with the fraction of feldspar inclusions. The results indicate that the feldspar inclusions probably account only for a portion of the observed fading. The results also indicate than an HF etch is not necessarily reliable for the removal of feldspars from quartz samples.