Through the application of new analytical techniques to high spatial resolution imaging spectrometer data, the ferrous mineralogy of major volcanic terrains on Mars is shown to consist of significant fractions of both low- and high-calcium pyroxene. Changes in the relative abundances of these pyroxenes are observed for units of different age and morphology, even in regions with higher degrees of alteration and contamination from dust. Volcanic rocks with these characteristics are uncommon on Earth but are typical of the basaltic SNC meteorites (shergottites, nakhlites, and chassignites) thought to be from Mars, Thus, it is possible to infer, even through the veil of dust, that the SNC meteorites have mineralogic affinities to major volcanic provinces on Mars and are therefore truly representative of the heterogeneity observed on the surface of the "red planet."