Distribution of dark material on Vesta Distribution of dark material on Vesta Dark material is found all over Vesta, most often associated with impact craters (circles on the map). It is also found in isolated spots (diamonds), many of which are probably secondary impact craters. In two locations, it's found near a topographic high: Lucaria Tholus (star in the southern hemisphere) and Aricia Tholus (star in the northern hemisphere). Also on the map are a black line for the outline of the Rheasilvia basin, and a red line for the incomplete rim of the Veneneia basin. Note that there are few exposures of dark material inside Rheasilvia, but many within and outside Veneneia. NASA / JPL / UCLA / MPS / DLR / IDA / map by Vishnu Reddy et al.