Rock Type: Muscovite-quartz pegmatoid
Location: Guyana, South America
Description: The sample is a complicated intergrowth of phengitic muscovite + quartz + hematite. The rock is dominated by coarse bundles of muscovite, coarse-grained quartz and the balance hematite. The hematite occurs interstitial to the muscovite and quartz and along grain margins. The muscovite is also being preferentially replaced by hematite along cleavage planes and in some instances wholesale replacement of muscovite by hematite is evident. The rock was studied for its gold potential.