Under ideal circumstances (flat surfaces, homogenous sample, data reduction using calibration curve based on similar rock types) the hXRF can provide data for several geologically-important elements that are comparable to laboratory XRF instruments. Our tests on the Apollo sample suite provided fairly accurate analyses of the samples (Table 2). The analyses were acquired using the same parameters (60 s on a flat surface, no other preparations), and in accordance with the laboratory rules for using the samples. What inconsistencies are present in the data are likely due to the high degree of compositional heterogeneities and the complex petrology common in lunar samples available for analysis. When compared to the relatively homogenous terrestrial sample standards selected for this study, the lunar samples analyzed here are remarkably complex. Analyses were completed on whichever sawed, flat surfaces already existed on the Apollo samples, meaning that there was not much flexibility in the precise locations where hXRF data could be taken. Despite the less-than-ideal analysis conditions, the hXRF was fairly accurate in determining the chemistry of these extraterrestrial samples, at least in the elements shown to be most robust with the calibration curves discussed above.