Martian meteorites are the only direct samples from Mars, thus far.
Currently, there are a total of 262 individual samples originating from
at least 11 ejection events. Geochemical analyses, through techniques
that are also used on terrestrial rocks, provide fundamental insights
into the bulk composition, differentiation and evolution, mantle
heterogeneity, and role of secondary processes, such as aqueous
alteration and shock, on Mars. Martian meteorites display a wide range
in mineralogy and chemistry, but are predominantly basaltic in
composition. Over the past six years, the number of martian meteorites
recovered has almost doubled allowing for studies that evaluate these
meteorites as suites of igneous rocks. However, the martian meteorites
represent a biased sampling of the surface of Mars with unknown ejection
locations. The geology of Mars cannot be unraveled solely by analyzing
these meteorites. Rocks analyzed by rovers on the surface of Mars are of
distinct composition to the meteorites, highlighting the importance of
Mars missions, especially sample return. The Mars 2020 Perseverance
rover will collect and cache --- for eventual return to Earth --- over
30 diverse surface samples from Jezero crater. These returned samples
will allow for Earth-based state-of-the-art analyses on diverse martian
rocks with known field context. The complementary study of returned
samples and meteorites will help constrain the evolution of the martian
interior and surface. Here, we review recent findings and advances in
the study of martian meteorites and examine how returned samples would
complement and enhance our knowledge of Mars.