Stream sediment chemistry and heavy mineral concentrates (HMC) are basic tools for exploring ore deposits. Fast analytical results are needed to optimize exploration strategies. Using an energy dispersive X-ray fluorescence (EDXRF) handheld fixed on a stage, the analysis could be done in the field providing informative results to optimize the exploration strategy. We investigated in the laboratory the effect of grain size on the chemical results for heavy mineral pan concentrates for four grain size fractions, namely <63 μm, 63–100 μm, 100–200 μm, and 200–630 μm. Data were compared with WDXRF laboratory results on fused beads of the bulk samples. Even values show different levels due to grain size fractionation, the overall trends are quite comparable to the bulk sample. The influence of the grain size effect becomes very obvious in the HMC, where some elements such as Au, Sn, etc. can be enriched in a certain fraction. Eventually, a bimodal distribution, for example, for zircon can be observed. Since heavy mineral concentration quality was not the same for all samples, some of them showing significant dilution by quartz and other silicates, and the smallest fractions are most probably not always preserved, absolute values are somehow irritating. For that reason element ratios were used to better highlight trends related to the lithologies. HMC could be attributed to granitoids, amphibolites, and schists. The HMC were sieved and, the grain size fractions were individually panned and gold was hand picked, quantified and investigated by SEM SE/BSE imaging. Gold grains were found to have suffered from variable degrees of transport and plastic deformation. Even the EDXRF method is sensitive for Au, these results were omitted, since fractions were panned before for gold. The use of EDXRF handheld in the field can be performed at low cost and minimum preparation effort on a rough overview basis. Amelioration of results can be achieved by more careful panning to reduce silicate based dilution and loss of the finest fractions. To reduce the grain size/pore effect on the results, hand milling could be applied to obtain the most accurate results. Despite the grain size and eventually nugget effect of the fractions, the non consistent panning quality, achieved results provide a better understanding of the mineralization of the area, the potentially hosting rocktypes and support localizing areas of interest in unknown terrain.