Compositional, mineralogical and structural investigation of meteorites by XRD and LIBS

Meteorites have been investigated in recent decades by employing various analytical techniques. In this chapter, an overview of investigations achieved by means of x-ray diffraction (XRD) and laser induced breakdown spectroscopy (LIBS) techniques, respectively, on mineralogical and compositional features, is presented. Results highlighted how a well-established technique like XRD possesses many intrinsic advantages, such as easy sample preparation, micro- or non-destructive nature, high sensitivity and reliability, possibility of qualitative and quantitative analysis, and structure solution both from single crystals or powders. Results on meteoritical minerals investigation, e.g. silicates, oxides, hydroxides, and phosphates, are provided. Further, a more recent technique suited for elemental analysis, LIBS, is gaining a very important role in the meteorite research field, owing to its strong sensibility to light elements such as H, Li, B, C, N, and O, to the possibility of analysis performed under reduced pressure conditions so avoiding any atmospheric interference, ease of use, no need of sample pretreatment, robustness and versatility, micro-destructive nature, and possibility to achieve compact transportable set ups. Results on the compositional variability of selected meteorite samples, in particular on martian specimens, are provided.