The Vega 2 lander determined the composition of rock in the area of the northern slope of the high-mountain massif Aphrodite Terra, which had never previously been analyzed. The rock was analyzed by X ray fluorescence analysis employing instrumentation similar to that on Venera 13 and 14. However, our experience with those probes made it possible to introduce some changes in the design of the device and in the program of its operation; as a result, the reliability of the device was improved. At the same time, the analytical characteristics of the instrument were improved: the range of the elements determined was expanded and the sensitivity was increased. The X ray fluorescence spectrometer operated on the Venusian surface in a preprogrammed mode. The abundances of the major rock-forming elements from Mg to Fe, inclusively, and also upper limits for some heavier rare elements, were determined. Comparison of these data with analyses of terrestrial rocks enables us, with certain reservations, to suggest that the analyzed Venusian sample is olivine gabbro-norite.